Thermoplastic resin composition

ABSTRACT

The thermoplastic resin composition disclosed herein comprises: 
     (1) a resin composition consisting of 
     (i) at least one member selected from the group consisting of 
     (a) a modified polypropylene to which has been graft copolymerized an unsaturated carboxylic acid or the derivative thereof, 
     (b) a modified polypropylene to which have been graft comodified an unsaturated aromatic monomer and either an unsaturated carboxylic acid or the derivative thereof, 
     (c) a mixture of the modified polypropylene (a) and a polypropylene, 
     (d) a mixture of the modified polypropylene (b) and a polypropylene, 
     (e) a modified mixture of a polypropylene and a rubbery substance to which mixture has been graft copolymerized an unsaturated carboxylic acid or the derivative thereof, 
     (f) a modified mixture of a polypropylene and a rubbery substance to which mixture have been graft copolymerized an unsaturated aromatic monomer and either an unsaturated carboxylic acid or the derivative thereof, 
     (g) a mixture of the modified mixture (e) and a polypropylene, and 
     (h) a mixture of the modified mixture (f) and a polypropylene, and 
     (ii) a thermoplastic copolymer (E) containing acid anhydride moiety of six-membered ring, and 
     (2) an epoxy group-containing copolymer (G). 
     The thermoplastic resin composition according to the present invention not only exhibits excellent processability but also produces remarkable advantages in that it gives far better physical properties than those expected from each polymer which constitutes the thermoplastic resin composition of the present invention. 
     The novel resin composition provided by the present invention can be easily processed into molded articles, films and sheets by a molding method generally used for thermoplastic resins such as injection molding, extrusion molding, etc, and can give products which have well-balanced properties among stiffness, heat resistance, impact resistance, scratch resistance, coatability, oil resistance, chemical resistance, water resistance, etc., and which are excellent in appearance uniformity and smoothness. The thermoplastic resin composition of the present invention is particularly suitable for use where well-balanced properties among heat resistance and impact resistance, low-temperature impact resistance in particular, are required.

The present invention relates to a novel thermoplastic resin compositionusable as a molded article, a sheet or a film formed by injectionmolding, extrusion molding, etc.

More specifically, it relates to a novel thermoplastic resin compositioncomprising an epoxy group-containing copolymer, a polypropylene resinand a thermoplastic copolymer containing an acid anhydride moiety of asix-membered ring, which composition has well-balanced properties and anexcellent appearance

Polypropylenes have heretofore been widely used in the form of variousmolded articles, films and sheets due to their excellent moldingprocessability, toughness, water resistance, gasoline resistance,chemical resistance, etc., and due to their low specific gravity and lowcost.

However, polypropylenes have defects, which should be improved, in heatresistance, stiffness, impact resistance, scratch resistance, coatingproperties, adhesive properties, printability, etc. These defectsconstitute an obstacle to introduction thereof to new areas in practicaluse.

For the purpose of improving coating properties, adhesive properties,printability, etc., of the above properties, for example, JP-B-58-47418and JP-A-58-49736, etc., propose a method of partially or whollygraft-modifying a Polypropylene with an unsaturated carboxylic acid orthe derivative thereof such as maleic anhydride However, even the use ofsuch a modified polypropylene does not essentially improve the impactresistance, heat resistance, stiffness and the other properties.

Meanwhile, being excellent in heat resistance, a thermoplastic copolymercontaining an acid anhydride moiety of a six-membered ring is inferiorin mechanical strength typified by impact resistance, and therefore, theuse thereof as a molding material is considerably limited in a practicalsense.

From such a viewpoint, a wide new area in use can be expected if athermoplastic resin having advantages of both a polypropylene resin anda thermoplastic copolymer containing an acid anhydride moiety of asix-membered ring can be obtained by blending the polypropylene resinselected from a modified polypropylene and a composition of apolypropylene and a modified polypropylene with a thermoplasticcopolymer containing an acid anhydride moiety of a six-membered ring.

However, it has been conventionally considered that a combination of apolypropylene resin with a thermoplastic copolymer containing an acidanhydride moiety of a six-membered ring is mutually poor incompatibility and dispersibility, and a mere blend of these actually hasthe following problems.

(1) A molten polymer shows a high Barus effect, and it is substantiallyimpossible to take up an extruded strand stably. Thus, moldingworkability is decreased to a great extent.

(2) An injection-molded article shows extreme nonuniformity and poorappearance due to occurrence of flow marks. Thus, such aninjection-molded article is not practically usable as an automobilepart, an electric or electronic part, etc.

(3) A molded article formed of a mixture of a Polypropylene resin with athermoplastic copolymer containing an acid anhydride moiety of asix-membered ring often shows lower values in mechanical properties suchas impact resistance, tensile elongation, etc., in particular thanexpected from the additivity of the individual properties of thesecomponents.

A resin for use in automobile parts, electric and electronic parts,etc., is required to show high-level performances such as high heatresistance, high impact resistance, etc.

It is therefore an object of the present invention to provide a novelthermoplastic resin composition having high heat resistance and highimpact resistance in particular and being well-balanced in otherproperties.

According to the present invention, there is provided a thermoplasticresin composition which comprises:

(1) 100 parts by weight of a resin composition (F) consisting of

(i) 1-99% by weight of at least one member selected from the groupconsisting of

(a) a modified polypropylene (A) to which has been graft copolymerizedan unsaturated carboxylic acid or the derivative thereof,

(b) a modified polypropylene (B) to which have been graft comodified anunsaturated aromatic monomer and either an unsaturated carboxylic acidor the derivative thereof,

(c) a mixture of the modified polypropylene (A) and a polypropylene (C),

(d) a mixture of the modified polypropylene (B) and a polypropylene (C),

(e) a modified mixture (A') of a polypropylene (C) and a rubberysubstance (H) to which mixture has been graft copolymerized anunsaturated carboxylic acid or the derivative thereof,

(f) a modified mixture (B') of a polypropylene (C) and a rubberysubstance (H) to which mixture have been graft copolymerized anunsaturated aromatic monomer and either an unsaturated carboxylic acidor the derivative thereof,

(g) a mixture of the modified mixture (A') and a polypropylene (C), and

(h) a mixture of the modified mixture (B') and a polypropylene (C), and

(ii) 99-1% by weight of a thermoplastic copolymer (E) containing acidanhydride moiety of six-membered ring, and

(2) 0.1 to 300 parts by weight of an epoxy group-containing copolymer(G).

One example of measurement charts in evaluation of penetration impactstrength is shown in FIG. 1, in which the abscissa axis indicates adisplacement amount (D: mm) for deformation of a test piece and theordinate axis indicates a stress (N: newton) to a displacement amount.

A yield point is a point where a stress to a displacement amount changesfrom increment to decrement, and a breaking point is a point where amaterial is fractured and a change in stress disappears.

A yield point energy is an area integration of a displacement amount andstress from a start of stress detection to a yield point of a material,and a total energy is an area integration of a displacement amount andstress from a start to a breaking point.

To begin with, the polypropylene is described in detail. The term"polypropylene" in the present specification is used to mean a startingmaterial for the modified polypropylene (A) or (B), or the modifiedmixture (A') or (B') of a polypropylene and a rubbery substance.

In the present invention, the "polypropylene" is a crystallinepolypropylene, which includes, besides a polypropylene homopolymer, ablock copolymer obtained by polymerizing propylene at a first step andcopolymerizing the resultant polypropylene with ethylene and a α-olefinsuch as propylene, butene-1, etc., at a second step; and a randomcopolymer obtained by copolymerizing propylene with not more than 6% bymole of an α-olefin such as ethylene, butene-1, etc.

The polypropylene homopolymer, block copolymer or random copolymer canbe generally produced by polymerization, e.g. in the presence of acombined catalyst of titanium trichloride with an alkyl aluminumcompound which is generally called a Ziegler-Natta catalyst.

The polymerization can be carried out at a temperature between 0° C. and300° C. In high-stereoregularity polymerization of an α-olefin such aspropylene, etc., however, a polymer having high stereoregularity cannotbe obtained at a temperature of more than 100° C. For this reason andsome others, the polymerization is carried out preferably at atemperature between 0° C. and 100° C.

The polymerization pressure is not critical, and can be desirablyselected from about 3 to about 100 atmospheric pressures from anindustrial and economical point of view.

The polymerization method may be any of a continuous method and a batchmethod.

The polymerization method can be selected from a slurry polymerizationmethod using an inert hydrocarbon solvent such as butane, pentane,hexane, heptane, octane, or the like; a solvent polymerization method inwhich the resulting polymer is dissolved in said inert hydrocarbonsolvent; a solventless bulk polymerization method in which a liquefiedmonomer is polymerized; and a gas phase polymerization method in which agaseous monomer is polymerized.

In order to regulate the molecular weight of the resultant polymer, achain transfer agent such as hydrogen may be added.

The polypropylene used in the present invention can be produced in thepresence of an isospecific Ziegler-Natta catalyst. The catalystpreferably has a high isospecificity.

It is preferred to use a catalyst whose transition metal catalystcomponent is a composite solid compound of a titanium trichloride ormagnesium compound having a laminar crystalline structure and a titaniumcompound, and whose typical metal component is an organoaluminumcompound. The catalyst may contain a known electron-donating compound asa third component.

The titanium trichloride is selected from those which are produced byreduction of titanium tetrachloride with a variety of reducing agents.As a reducing agent, there are known metals such as aluminum, titanium,etc., hydrogen, an organometal compound, and the like. A typical exampleof the titanium trichloride produced by metal reduction is a titaniumtrichloride composition containing activated aluminum chloride (TiCl₃AA), produced by reducing titanium tetrachloride with metal aluminum andthen pulverizing the resultant mixture in an apparatus such as a ballmill or a vibration mill. In order to improve isospecificity,polymerization activity and/or particulate properties of the catalyst,the above pulverization may be carried out in the presence of a compoundselected from an ether, a ketone, and ester, aluminum chloride, titaniumtetrachloride, etc.

Further preferred for the object of the present invention is titaniumtrichloride which is obtained by reducing titanium tetrachloride with anorganoaluminum compound, and catalytically reacting the resultanttitanium trichloride with an ether compound and with a halogen compoundat the same time or consecutively. The ether compound preferably has thegeneral formula of R¹ --O--R² in which each of R¹ and R² is an alkylgroup having 1 to 18 carbon atoms, and particularly preferred aredi-n-butyl ether and di-t-amyl ether. In particular, a preferred halogenis iodine, the preferred halogen compound is iodine trichloride, apreferred titanium halide is titanium tetrachloride, and a preferredhalogenated hydrocarbon is selected from carbon tetrachloride and1,2-dichloroethane. The organoaluminum compound has general formula ofAIR³ _(n) X_(3-n) in which R³ is a hydrocarbon carbon group having 1 to18 carbon atoms, X is a halogen selected from Cl, Br and I, and n isdefined by 3 ≧ n > 1, and diethylaluminum chloride and ethylaluminumsesquichloride are particularly preferred.

The process for the production of the above titanium trichloride isspecifically disclosed in JP-A-47-34470, JP-A-53-33289, JP-A-53-51285,JP-A-54-11986, JP-A-58-142903, JP-A-60-28405, JP-A-60-228504,JP-A-61-218606, etc.

When titanium trichloride having a laminar crystalline structure is usedas a transition metal compound component, it is preferred to use, as atypical metal compound component, an organoaluminum compound having thegeneral formula of AIR⁴ _(m) X_(3-m) in which R⁴ is a hydrocarbon grouphaving 1 to 18 carbon atoms, X is a halogen selected from Cl, Br and I,and m is defined by 3 ≧ m > 0. Particularly preferred for the object ofthe present invention is a compound of the above general formula inwhich R⁴ is an ethyl or isobutyl group and m is defined by 2.5 ≧ m >1.5. Specific examples thereof are diethylaluminum chloride,diethylaluminum bromide, diethylaluminum iodide, and mixtures of thesewith triethylaluminum or ethylaluminum dichloride. When a thirdcomponent to be discussed later is used in combination, preferred forthe object of the present invention is also an organoaluminum compoundof the above general formula in which m is defined by 3 ≧ m > 2.5 or 1.5≧ m > 0.

The molar ratio of organoaluminum compound to titanium trichloride canbe selected from between 1 : 1 and 1,000 : 1.

The catalyst comprising titanium trichloride and organoaluminum maycontain a known third component. Examples of the third component areester compounds such as ε-caprolactam, methyl methacrylate, ethylbenzoate, methyl totluylate, etc., phosphite esters such as triphenylphosphite, tributyl phosphite, etc., and phosphoric acid derivativessuch as hexamethylphosphorictriamide, etc., and the like.

The amount of the third component may be experimentally determined,since the activity varies depending upon the compounds above. Ingeneral, it is not more than an equimolar amount to that of theorganoaluminum.

When a composite solid compound of a magnesium compound and a titaniumcompound is used as a transition metal solid catalyst component, it ispreferred to use, as a typical metal catalyst component, anorganoaluminum compound, and it is particularly preferred to use acompound having the general formula of AIR⁵ _(p) X_(3-p) in which R⁵ isa hydrocarbon group having 1 to 18 carbon atoms, X is a halogen selectedfrom Cl, Br and I and p is defined by 3 ≧ p > 2. Specific examplesthereof are triethylaluminum, triisobutylaluminum and mixtures of thesewith diethylaluminum chloride or diisobutylaluminum chloride.

The catalyst also preferably contains an electron-donating compound,particularly an aromatic monocarboxylic acid ester and/or a siliconcompound containing an Si--OR⁶ bond.

As a silicon compound containing an Si--OR⁶ bond in which R⁶ is ahydrocarbon group having 1 to 20 carbon atoms, preferred is analkoxysilane compound having the general formula of R⁷ _(a)Si(OR⁶)_(4-a) in which each of R⁶ and R⁷ is independently a hydrocarbongroup having 1 to 20 carbon atoms and a is defined by 0 ≦ a ≦ 3.Specific examples thereof are tetramethoxysilane,methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane,phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane,ethyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane,diphenyldimethoxysilane, diphenyldiethoxysilane, butyltriethoxysilane,tetrabutoxysilane, vinyltributoxysilane, diethyldiethoxysilane, etc.

The amount of the above electron-donating compound for use is preferablynot more than 1 mole, particularly preferably 0.05 to 1 mole per mole ofthe organoaluminum compound.

The composite solid compound of a magnesium compound and a titaniumcompound is selected from titanium trichloride containing a chloride ofmagnesium obtained by reducing titanium tetrachloride with anorganomagnesium compound, and a so-called "supported catalyst" preparedby catalytically reacting a solid magnesium compound with a liquid-phasetitanium compound. The solid magnesium compound preferably contains anelectron-donating compound, particularly an aromatic monocarboxylic acidester, an aromatic dicarboxylic acid diester, an etherified compound, analcohol and/or a phenolic compound. The aromatic monocarboxylic acidester may be co-present when the solid magnesium compound iscatalytically reacted with the titanium compound.

The above composite solid compound of the magnesium compound and thetitanium compound is disclosed in many patent publications, and thosesuitable for the object of the present invention are specificallydisclosed in JP-A-54-112988, JP-A-54-119586, JP-A-56-30407,JP-A-57-59909, JP-A-57-59910, JP-A-57-59911, JP-A-57-59912,JP-A-57-59914, JP-A-57-59915, JP-A-57-59916, JP-A-54-112982,JP-A-55-133408, JP-A-58-27704, etc.

When the thermoplastic resin composition of the present invention isused in fields where heat resistance, stiffness, scratch resistance,etc., are particularly required, it is desirable to use a highlycrystalline polypropylene which is a homopolymer of polypropylene or apolypropylene block copolymer, wherein the homopolymer or thehomopolymer portion as a first segment polymerized in the first step forthe block copolymer has an isotactic pentad of the boiling heptaneinsoluble portion of 0.970 or more, a content of the boiling heptanesoluble portion of not more than 5% by weight and a content of the 20°C. xylene soluble portion of not more than 2.0% by weight.

The above isotactic pentad of the boiling heptane insoluble portion, thecontent of the boiling heptane soluble portion and the content of the20° C. xylene soluble portion are determined as follows.

Five grams of a Polypropylene is completely dissolved in 500 ml ofboiling xylene, the resultant solution is cooled to 20° C., and thesolution was allowed to stand for 4 hours. Then, the solution wasfiltered to separate a 20° C. xylene insoluble portion. Xylene wasevaporated by concentrating the filtrate and solidifying it by drying,and the residue is further dried under reduced pressure at 60° C. toobtain a polymer soluble in xylene at 20° C. The content of the 20° C.xylene soluble portion is determined by dividing the dry weight of thesoluble polymer sample by the weight of the charged sample, andrepresented by percentage. The above 20° C. xylene insoluble portion isdried, and then extracted with boiling n-heptane in a Soxhlet apparatusfor 8 hours. The extraction residue is referred to as a boiling heptaneinsoluble portion, and the content of the boiling heptane solubleportion is determined by subtracting the dry weight of the boilingheptane insoluble portion from the weight of the charged sample ( 5 g)and dividing the remainder by the weight of the charged sample, andrepresented by percentage.

The isotactic pentad refers to a fraction of a propylene monomer unitpresent in the central position of an isotactic chain of a polypropylenemolecule chain in a pentad unit, in other words, in a chain formed ofmeso-bonded five successive propylene monomer units, determined by amethod disclosed by A. Zambelli et al., in Macromolecules, 6, 925(1973), which utilizes ¹³ C-NMR. NMR absorption peaks are assigned onthe basis of the subsequently issued Macromolecules, 8, 687 (1975).

Specifically, the isotactic pentad is determined on the basis of arelative ratio of the area of mmmm peaks to the total area of theabsorption peaks assigned to methyl carbons. According to this method,the NPL standard substance CRM No. M19-14 Polypropylene PP/WWD/2provided by the National Physical Laboratory in United Kingdom wasmeasured for an isotactic pentad to show 0.944.

The above highly crystalline polypropylene can be prepared, for example,by any of the methods disclosed in JP-A-60-28405, JP-A-60-228504,JP-A-61-218606, JP-A-61-287917, etc.

when the thermoplastic resin composition of the present invention isused in fields where impact resistance is required, it is preferred touse a polypropylene block copolymer obtained by copolymerizing apropylene homopolymer portion as the first segment having beenpolymerized in the first step with ethylene and an α-olefin such aspropylene butene-1, etc., which constitute the second segment, in thesecond step.

The propylene block copolymer can be prepared by a slurry polymerizationor gas phase polymerization method. In particular, when thethermoplastic resin composition is used in a fluid where high impactresistance is required, it is required to increase the amount of thesecond segment, and such a propylene block copolymer can be suitablyprepared by a gas phase polymerization method.

The polypropylene having high impact resistance can be prepared by a gasphase polymerization method disclosed, e.g. in JP-A-61-287917.

In the propylene block copolymer, the propylene homopolymer portionpolymerized in the first step may be any of a propylene homopolymer or acopolymer of propylene with ethylene or an α-olefin having 4 to 6 carbonatoms wherein the content of the ethylene or α-olefin units is not morethan 6 mole%. The copolymer Portion as the second segment polymerized inthe second step is preferably a homopolymer of ethylene or a copolymerof ethylene, propylene and optionally an α-olefin having 4 to 6 carbonatoms wherein the ethylene content is not less than 10 mole%. The amountof the polymer formed in the second step is 10 to 70% by weight based onthe total polymer weight.

The slurry polymerization method gives a propylene block copolymerhaving a second segment content of 10 to 30% by weight, and the gasphase polymerization method gives a propylene block copolymer having asecond segment content of 10 to 70% by weight.

In the gas phase polymerization method, a propylene block copolymerhaving a larger content of the second segment can be prepared by aprocess disclosed in JP-A-1-98604 (1989), and such a copolymer can besuitably used in a field where ultrahigh impact resistance is required.

The intrinsic viscosity of the second segment in tetralin at 135° C.should be changed depending upon production efficiency, physicalproperties of a polymer powder and an intrinsic viscosity of the firstsegment. In general, however, it is 3-8 dl/g for the slurrypolymerization method and 1 to 5 dl/g for the gas phase polymerizationmethod.

In the present invention, the modified polypropylene (A) or (B) meansthat which is obtained by graft-polymerizing an unsaturated carboxylicacid or the derivative thereof, or a mixture of an unsaturatedcarboxylic acid or the derivative thereof and an unsaturated aromaticmonomer onto a polypropylene, if necessary, in the presence of a radicalinitiator.

When the above monomers are grafted to a polypropylene, variousconventional methods can be employed.

For example, the grafting can be carried out by a method which comprisesmixing polypropylene, a graft monomer and a radical-generating agent andmelt-kneading the resultant mixture in a melt-kneading apparatus, or bya method which comprises dissolving polypropylene in an organic solventsuch as xylene, adding a radical-generating agent under a nitrogenatmosphere, carrying out a reaction of the resultant mixture by heatingit with stirring, cooling the reaction mixture after the reaction,washing the reaction product, filtering it and drying it. Besides theabove methods, there can be employed a method which comprisesirradiating a polypropylene with ultraviolet light or radiation in thepresence of a graft monomer or a method which comprises bringing apolypropylene into contact with oxygen or ozone in the presence of agraft monomer.

In view of economical efficiency, etc., the most preferred is the graftpolymerization method which comprises melt-kneading a polypropylene anda graft monomer in a melt-kneading apparatus.

The melt-kneading of a polypropylene and an unsaturated carboxylic acidor the derivative thereof, or a polypropylene and a mixture of anunsaturated carboxylic acid or the derivative thereof and an unsaturatedaromatic monomer in the presence of a radical initiator, if necessary,can be carried out with an extruder, a Banbury mixer, a kneader, etc. ata temperature of 150° to 300° C., preferably 190° to 280° C. for aresidence time of 0.3 to 10 minutes, preferably 0.5 to 5 minutes. It isindustrially advantageous to continuously produce a modifiedpolypropylene with a single- or twin-screw extruder with keeping thevent holes in a vacuous state and removing unreacted components(unsaturated carboxylic acid or the derivative thereof, unsaturatedaromatic monomer, radical initiator, etc.) and by-products such asoligomers and decomposition products of these components. The reactionmay be carried out in an atmosphere of air, but is preferably carriedout in an atmosphere of an inert gas such as nitrogen or carbon dioxide.In addition, in order to further remove a trace amount of unreactedcomponents and by-products contained in the modified polypropyleneobtained, the modified polypropylene may be heat-treated at atemperature of 60° C. or higher, extracted with a solvent or vacuumedwhile melted.

A variety of additives may be optionally added to the modifiedpolypropylene (A) or (B) during the modification or post-treatment.Examples of such additives are an antioxidant, a heat stabilizer, alight stabilizer, a nucleating agent, a lubricant, an antistatic agent,an inorganic or organic colorant, a rust preventive, a crosslinkingagent, a foaming agent, a plasticizer, a fluorescent agent, a surfacetreating agent, a surface brightener, etc.

Examples of the unsaturated carboxylic acid or the derivative thereof,used for the polypropylene modification, are unsaturated carboxylicacids such as acrylic acid, methacrylic acid, maleic acid, itaconicacid, citraconic acid, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid(himic acid), bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic acid,4-methylcyclohex-4-ene1,2-dicarboxylic acid,1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic acid,bicyclo[2.2.1]-oct-7-ene-2,3,5,6-tetracarboxylic acid,7-oxabicyclo[-2.2.1]hept-5-ene-2,3-dicarboxylic acid, etc.; and acidanhydrides, esters, amides, imides and metal salts of an unsaturatedcarboxylic acid such as maleic anhydride, itaconic anhydride, citraconicanhydride, bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid anhydride(himic anhydride), monoethyl maleate, monomethyl fumarate, monomethylitaconate, dimethylaminoethyl methacrylate,dimethylaminopropylacrylamide, acrylamide, methacrylamide, maleic acidmonoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleicacid-N,N-diethylamide, maleic acid-N-monobutylamide, maleicacid-N,N-dibutylamide, fumaric acid monoamide, fumaric acid diamide,fumaric acid-N-monoethylamide, fumaric acid-N,N-diethylamide, fumaricacid-N-monobutylamide, fumaric acid-N,N-dibutylamide, maleimide,N-butylmaleimide, N-phenylmaleimide, sodium acrylate, sodiummethacrylate, potassium acrylate, potassium methacrylate, etc.

Of these, maleic anhydride is preferred.

Although styrene is preferred as an unsaturated aromatic monomer,o-methylstyrene, p-methylstyrene, m-methylstyrene, α-methylstyrene,vinyltoluene, vinylbenzene, etc., can be also used. These compounds maybe used in combination.

The polypropylene modification can be also carried out in the absence ofa radical initiator. In general, however, it is carried out preferablyin the presence of a radical initiator. Known radical initiators areusable as such. Examples of the radical initiator are azo compounds suchas 2,2'-azobisisobutyronitrile,2,2'-azobis(2,4,4)-trimethylvaleronitrile, etc.; and various organicPeroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide,3,3,5-trimethylcyclohexanone peroxide, 2,2-bis(t-butylperoxy)butane,t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzenehydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butylperoxide, 1,3-bis(t-butylperoxyisopropyl)benzene,2,5-dimethyl-2,5-di(t-butylperoxy)hexane,2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, lauroyl peroxide,3,3,5-trimethylhexanoyl peroxide, benzoyl peroxide, t-butyl peracetate,t-butylperoxyisobutyrate, t-butyloxypivarate,t-butylperoxy-2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate,t-butylperoxylaurate, t-butylperoxybenzoate,di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane,t-butylperoxymaleic acid, t-butylperoxyisopropylcarbonate, polystyreneperoxide, etc.

In the modification, the melt flow rate of the polypropylenes as astarting material (crystalline propylene homopolymer, crystallinepropylene-ethylene/ α-olefin block copolymer and crystallinepropyleneethylene/α-olefin random copolymer) is not critical. Usually,however, it is 0.05 to 60 g/10 minutes, preferably 0.1 to 40 g/10minutes. Further, it is desirable to select a polypropylene as astarting material so that the melt flow rate of the resultant modifiedpolypropylene (A) or (B) preferably falls within the range of 0.1 to 100g/10 minutes, more preferably 0.5 to 70 g/10 minutes. The polypropyleneas a starting material usually has a number average molecular weight of7,000 to 800,000, preferably 10,000 to 700,000.

For the modification, the amount of each component per 100 parts byweight of the polypropylene is as follows. The amount of the unsaturatedcarboxylic acid or the derivative thereof is preferably 0.01 to 10 partsby weight, more preferably 0.1 to 5 parts by weight, and that of theradical initiator is preferably 0 to 5 parts by weight, more preferably0.001 to 2 parts by weight. When the amount of the unsaturatedcarboxylic acid or the derivative thereof is less than 0.01 part byweight, there are cases where no remarkable effect can be produced onthe modification. When it exceeds 10 parts by weight, the effect on themodification tends to arrive at its limit, and sometimes any furthereffect is not exhibited. Moreover, the use of such an excess amounttends to be practically undesirable, since a large amount of theunsaturated carboxylic acid or the derivative thereof remainingunreacted in the resultant polymer sometimes causes offensive smell anddegradation in physical properties of the thermoplastic resincomposition. The use of the radical initiator in an amount of more than5% by weight tends to be practically undesirable, since it sometimesgives no further remarkable effect on the graft reaction of theunsaturated carboxylic acid or the derivative thereof and since thepolypropylene is sometimes decomposed to a great extent to change thefluidity (melt flow rate) greatly.

In the present invention, the modified polypropylene-based resincomposition (D) includes (a) a modified polypropylene (A) to which hasbeen graft copolymerized an unsaturated carboxylic acid or thederivative thereof, (b) a modified polypropylene (B) to which have beengraft copolymerized an unsaturated aromatic monomer and either anunsaturated carboxylic acid or the derivative thereof, (c) a mixture ofthe modified polypropylene (A) and a polypropylene (C) or (d) a mixtureof the modified polypropylene (B) and a polypropylene (C). Preferred arethose having a melt flow rate of 0.1 to 100 g/10 minutes, andparticularly preferred are those having a melt flow rate of 0.5 to 40g/10 minutes.

The thermoplastic copolymer containing an acid anhydride moiety of asix-membered ring, used in the present invention, is preferably selectedfrom those which contain 10 to 95% by weight, preferably 15 to 90% byweight, of (1) methyl methacrylate units, and 5 to 35% by weight,preferably 8 to 30% by weight of (2) methacrylic acid and/or acrylicacid units and (3) units of acid anhydride moiety of six-membered ringof the formula, ##STR1##

Wherein R and R' are independently methyl or hydrogen, the content ofsaid units of acid anhydride moiety of six-membered ring being not lessthan 55% by weight, preferably not less than 60% by weight based on thetotal amount of (2) and (3), and which optionally contains, at most 55%by weight, preferably at most 50% by weight of (4) an α,β-ethylenicallyunsaturated monomer.

When the amount of the methyl methacrylate units (1) in the abovecopolymer is less than 10% by weight, the strength of the copolymertends to be undesirably deteriorated. When this amount is more than 95%by weight, the heat deformation resistance is sometimes insufficient andundesirable.

When the total amount of the methacrylic acid and/or acrylic acid units(2) and the units of the acid anhydride of six-membered ring (3) is lessthan 5% by weight, there are some cases where improvement in the heatdeformation resistance is insufficient.

Further, when the amount of the above (3) based on the total amount ofthe above (2) and (3) is less than 55% by weight, the water absorptionratio is liable to increase, and, there are some cases, with regard tomoldability, where a splash mark (silver streaks) occurs and impairs amolded article appearance.

This copolymer is required to have a suitable molecular weight since itis processed by molding. When the molecular weight of this copolymer is,expressed by way of a reduced viscosity (N,N-dimethylformamide solvent,1% concentration, 25° C.), the value for the reduced viscosity thereofis preferably in the range of from 0.3 to 1.5 dl/g.

When this value is less than 0.3 dl/g, the mechanical properties areliable to be low. When it exceeds 1.5 dl/g, the fluidity tends to bedecreased, and the processability tends to be deteriorated.

The α,β-ethylenically unsaturated monomer (4) is selected from thosewhich are usually used as a monomer for general purpose thermoplasticresin.

Examples thereof are olefins, vinyl chloride, acrylonitrile, aromaticvinyl compounds, unsaturated carboxylic acid alkyl esters, etc.

Of these, preferred are one or more members selected from unsaturatedcarboxylic acid alkyl esters and aromatic vinyl compounds.

Specific examples of the unsaturated carboxylic acid alkyl esters aremethacrylic acid esters and acrylic acid esters, and more specifically,they are n-butyl methacrylate, t-butyl methacrylate, n-bornylmethacrylate, isobornyl methacrylate, fenchyl methacrylate, cyclohexylmethacrylate, phenyl methacrylate, benzyl methacrylate, dicyclopentanylmethacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, etc.Specific examples of the aromatic vinyl compounds are styrene,α-methylstyrene, etc.

This copolymer is prepared as follows. At first, one or more membersselected out of methyl methacrylate, methacrylic acid and acrylic acid,and optionally, other copolymerizable α,β-ethylenically unsaturatedmonomer are polymerized in the presence of a radical initiator and inthe presence of a chain transfer agent by a known suspensionpolymerization, bulk polymerization, emulsion polymerization or solutionpolymerization method, whereby a precursor copolymer is obtained.

Thereafter, the precursor copolymer is subjected to a cyclizationpolymerization to form a cyclic product of the methacrylic acid.

In general, the above cyclization reaction is carried out by onlyheating the base copolymer at 150° to 350° C. as described inJP-A-49-85184, JP-A-58-217501, etc.

In order to accelerate the reaction efficiently, it is possible toemploy a method using a ring-closing promoter such as a method using abasic compound as described in JP-A-254608 or a method using an organiccarboxylic acid salt and/or a carbonic acid salt as described inJP-A-61-261303.

The reduced viscosity can be adjusted with using a chain transfer agentwhen said precursor copolymer is prepared.

The epoxy group-containing copolymer (G) in the present invention is acopolymer composed of an unsaturated epoxy compound and an ethylenicallyunsaturated compound.

The composition ratio of the epoxy group-containing copolymer (G) is notcritical. In general, however, preferred is a copolymer containing 0.1to 50% by weight, preferably 1 to 30% by weight of an unsaturated epoxycompound.

The unsaturated epoxy compound is a compound containing an epoxy groupand an unsaturated group copolymerizable with an ethylenicallyunsaturated compound in the molecule.

Specific examples of the unsaturated epoxy compound are unsaturatedglycidyl esters and unsaturated glycidyl ethers which have the followingformulae (2) and (3), respectively. ##STR2## wherein R is a C₂ -C₁₈hydrocarbon group having an ethylenically unsaturated bond. ##STR3##wherein R is a C₂ -C₁₈ hydrocarbon group having an ethylenicallyunsaturated bond, and X is ##STR4##

Specific examples of the unsaturated epoxy compound are glycidylacrylate, glycidyl methacrylate, glycidyl itaconate, allylglycidylether, 2-methylglycidyl ether, styrene-p-glycidyl ether, etc.

Examples of the ethylenically unsaturated compound are olefins, vinylesters of a saturated carboxylic acid having 2 to 6 carbon atoms, estersof at least one saturated alcohol having 1 to 8 carbon atoms with anyone of acrylic acid, methacrylic acid, maleic acid, methacrylic acid andfumaric acid, vinyl halides, styrenes, nitriles, vinyl ethers,acrylamides, etc.

Specific examples of the ethylenically unsaturated compound areethylene, propylene, butene-1, vinyl acetate, methyl acrylate, ethylacrylate, methyl methacrylate, dimethyl maleate, diethyl fumarate, vinylchloride, vinylidene chloride, styrene, acrylonitrile, isobutylvinylether, acrylamide, etc. Of these, ethylene is particularly preferred.

In order to improve the low-temperature impact resistance by decreasinga glass transition temperature, it is preferable to use vinyl acetateand/or methyl acrylate, etc., as a third component in addition toethylene as a second component.

The amount of the third component is not critical. In general, thisamount is not more than 20% by weight, preferably 5 to 15% by weight.

The epoxy group-containing copolymer can be prepared by various methods.It is possible to employ a random copolymerization method comprisingintroducing an unsaturated epoxy compound into the main chain of thecopolymer and a graft copolymerization method comprising introducing anunsaturated epoxy compound as a branch for the copolymer. Specificexamples of the preparation method are a method which comprisescopolymerizing an unsaturated epoxy compound and ethylene in thepresence of a radical-generating agent at 500 to 4,000 atmosphericpressures at 100° to 300° C. in the presence or absence of a suitablesolvent and a chain transfer agent, a method which comprises mixing apolypropylene with an unsaturated epoxy compound and aradical-generating agent and subjecting the resultant mixture to meltgraft polymerization in an extruder, and a method which comprisescopolymerization an unsaturated epoxy compound and an ethylenicallyunsaturated compound in an inert medium such as water or an organicsolvent in the presence of a radical-generating agent.

When the thermoplastic resin composition of the present invention isproduced, a basic compound (J) may be co-present in order to promote thereaction between an unsaturated carboxylic acid or the derivativethereof having been graft polymerized to the modified polypropylene (A)or (B), to the modified polypropylene (A') or (B') or to a rubberysubstance (I) and the epoxy group of the epoxy group-containingcopolymer (G), and the reaction between the unreacted terminalcarboxylic acid of the thermoplastic copolymer (E) containing an acidanhydride moiety of a six-membered ring and the epoxy group of the epoxygroup-containing copolymer (G).

The co-presence of the basic compound (J) can shorten the reaction timeand shorten the time required for the production. For example, organicamine compounds such as benzyldimethylamine,2,4,6-tris(dimethylaminomethyl)phenol, etc., are preferred as the basiccompound (J).

In the production of the thermoplastic resin composition, the abovebasic compound may be mixed with the starting materials for thethermoplastic resin composition, or it may be preliminary mixed with aportion of the starting materials or with a resin compatible with thethermoplastic resin composition so as to prepare a high-concentrationmaster batch.

The rubber substance (H) used to improve the impact resistance,low-temperature impact resistance in particular, can be selected fromethylene copolymer rubbers, propylene-butene rubbers, isoprene-butylenerubbers, polyisoprenes, polybutadienes, styrene block copolymers such asstyrene-butadiene rubbers, styrenebutadiene-styrene block copolymers,partially hydrogenated styrene-butadiene block copolymers,styreneisoprene block copolymers, partially hydrogenatedstyrene-isoprene block copolymers, etc., linear low-densitypolyethylenes, and mixtures of these.

Examples of the ethylene copolymer rubbers are various ethylenecopolymer rubbers such as ethyleneα-olefin copolymer rubbers orethylene-α-olefinnonconjugated diene copolymer rubbers typical examplesof which are ethylene-propylene copolymer rubbers (hereinafter EPM) andethylene-propylene-nonconjugated diene copolymer rubbers (hereinafterEPDM), ethylenevinyl acetate copolymers, ethylene-methyl acrylatecopolymers, ethylene-methyl methacrylate copolymer rubbers,ethylene-ethyl acrylate copolymers, ethylene-ethyl methacrylatecopolymers, ethylene-butyl acrylate copolymers, ethylene-butylmethacrylate copolymers, ethylene-acrylic acid copolymers,ethylene-methacrylic acid copolymers, copolymers of a partial metal saltof ethylene-acrylic acid, copolymers of a partial metal salt ofethylene-methacrylic acid, ethylene-acrylic acid-acrylic esterterpolymers, ethylene-acrylic acid-methacrylic ester terpolymers,ethylene-methacrylic acid-acrylic ester terpolymers,ethylene-methacrylic acid-methacrylic ester terpolymers, ethylene-vinylalcohol copolymers, ethylene-vinyl acetate-vinyl alcohol terpolymers,ethylene-styrene copolymers, etc. And, these ethylene copolymer rubberscan be used in combination. Further, these ethylene copolymer rubberscan be used by mixing them with a low-density or high-densitypolyethylene which is well compatible with these. The modified rubberysubstance (I) is obtained by graft-polymerizing an unsaturatedcarboxylic acid or the derivative thereof, or an unsaturated carboxylicacid or the derivative thereof and an unsaturated aromatic monomer, ontothe above rubbery substance (H), if necessary, in the co-presence of aradical initiator, or alternatively by introducing an unsaturatedcarboxylic acid or the derivative thereof, or a mixture of anunsaturated carboxylic acid or the derivative thereof with anunsaturated aromatic monomer, into the α-olefin main chain in thepresence of a polymerization initiator and a catalyst.

The starting rubbery material for the rubbery substance (H) and themodified rubbery substance (I) can be particularly suitably selectedfrom ethylene copolymers and styrene block copolymers.

Of the ethylene copolymer rubbers, particularly preferred areethylene-α-olefin copolymer rubbers and ethylene-α-olefin nonconjugatedcopolymer rubbers. Examples of the ethylene-α-olefin copolymer rubbersinclude copolymers of ethylene and another α-olefin such as propylene,1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, or thelike, and terpolymer rubbers such as an ethylene-propylene-1-buteneterpolymers. Of these, ethylene-propylene copolymer rubbers andethylene-1-butene copolymer rubbers are preferred.

Further, ethylene-α-olefin-nonconjugated diene terpolymer rubbers can bealso used. However, it is preferable to adjust the nonconjugated dienecontent in the starting material rubber to not more than 3% by weight.When the nonconjugated diene content exceeds 3% by weight, there aresome cases where the composition undesirably undergoes gelation when itis kneaded.

The ethylene content in the ethylene-α-olefin copolymer rubber isusually 15 to 85% by weight, preferably 40 to 80% by weight. That is,there are some cases where a highly crystalline polymer having anethylene content of more than 85% by weight is difficult to processunder ordinary rubber-forming conditions, and that having an ethylenecontent of less than 15% by weight is liable to show an increase inglass transition temperature (Tg) and undesirably lose rubberproperties.

The number average molecular weight of the ethylene-α-olefin copolymerrubber preferably falls within the range which permits kneading in anextruder and it usually of from 10,000 to 100,000. When the molecularweight is too low, the feeding of the ethylene-α-olefin copolymer rubberto an extruder tends to be difficult, and when it is too high, there aresome cases where the ethylene-α-olefin copolymer rubber shows a lowfluidity and tends to cause difficulty in processing.

The molecular weight distribution of the ethylene-α-olefin copolymerrubber is not critical. Usually, there can be used any of conventionallymanufactured and commercially available copolymer rubbers having avariety of molecular weight distributions such as a monomodaldistribution and a bimodal distribution.

The Q value (weight average molecular weight/ number average molecularweight) of the molecular weight distributions is preferably in the rangeof 1 to 30, more preferably 2 to 20.

In summary, the copolymer rubber is that which is produced in thepresence of the so-called ZieglerNatta catalyst, i.e. a catalystconventionally used for the production. For example, a combination of anorganoaluminum compound with a trivalent to pentavalent vanadiumcompound soluble in a hydrocarbon solvent is used as a Ziegler-Nattacatalyst. The aluminum compound can be selected from alkylaluminumsesquichloride, trialkylaluminum, dialkylaluminum monochloride, andmixtures of these. The vanadium compound can be selected from vanadiumoxytrichloride, vanadium tetrachloride and a vanadate compound of theformula VO(OR⁸)_(q) X_(3-q) wherein 0 < q ≦ 3, R⁸ is a linear, branchedor cyclic hydrocarbon having 1 to 10 carbon atoms, and X is a halogenselected from Cl, Br and I.

Of the styrene block copolymers, particularly preferred are partiallyhydrogenated styrene-butadiene block copolymers. The partiallyhydrogenated styrene-butadiene block copolymer is produced by partialhydrogenation of a styrene-butadiene block copolymer. The structure andproduction process thereof are described below.

The number average molecular weight of the copolymer rubber block in thepartially hydrogenated styrene-butadiene block copolymer is usually10,000 to 1,000,000, preferably 20,000 to 300,000. The number averagemolecular weight of the unsaturated aromatic copolymer block in thepartially hydrogenated styrene-butadiene block copolymer is usually1,000 to 200,000, preferably 2,000 to 100,000. The number averagemolecular weight of the nonconjugated diene copolymer block in thepartially hydrogenated styrene-butadiene block copolymer is usually1,000 to 200,000, preferably 2,000 to 100,000. And the weight ratio ofthe unsaturated aromatic copolymer block to the nonconjugated dienecopolymer block is usually 2 : 98 to 60 : 40, preferably 10 : 90 to 40 :60.

Many processes have been proposed for the production of the blockcopolymer rubber. A typical process is disclosed in Japanese PatentPublication Kokoku No. 40-23798, in which a block copolymer rubber of anunsaturated aromatic hydrocarbon and a diene hydrocarbon can be producedby block copolymerization in an inert solvent in the presence of alithium catalyst or a Ziegler catalyst.

Such a block copolymer rubber is hydrogenated in an inert solvent in thepresence of a hydrogenation catalyst, e.g. according to any one of themethods disclosed in Japanese Patent Publications Kokoku Nos. 42-8704,43-6636 and 46-20814. The hydrogenation in this case is carried out insuch a way that the hydrogenation ratio of the polymer block B isusually at least 50%, preferably 80% or more and that the hydrogenationratio of the aromatic unsaturated bond in the unsaturated aromaticpolymer block is not more than 25%. One typical example of such apartially or completely hydrogenated block copolymer is on the market inthe trade name KRATON®-G, supplied by Shell Chemical Co., U.S.A.

In the production of the modified rubbery substance (I), the method forgraft-copolymerizing a graft monomer to the rubbery substance can beselected from a variety of known methods.

For example, the graft copolymerization is carried out by a method whichcomprises mixing a starting rubbery substance, a graft monomer and aradical initiator and melt-kneading the mixture in a melt-kneadingapparatus to effect grafting, or a method which comprises dissolving anethylene copolymer rubber in an organic solvent such as xylene, addingthereto a radical initiator under a nitrogen atmosphere, allowing themixture to react under heat with stirring, cooling the reaction mixtureafter the reaction, washing the reaction product, filtering it anddrying it thereby to obtain a grafted ethylene copolymer rubber. Inaddition to these, there are a method which comprises irradiating anethylene copolymer rubber with ultraviolet light or radiation in thepresence of a graft monomer, and a method which comprises bringing arubbery substance into contact with oxygen or ozone.

In view of economical benefit, it is most preferred to employ a graftcopolymerization method in which the above materials are melt-kneaded ina melt-kneading apparatus.

In the present invention, the modified rubbery substance (I) can beobtained by melt-kneading the starting rubbery substance with anunsaturated carboxylic acid or the derivative thereof in the optionalcopresence of a radical initiator, or by melt-kneading the startingrubbery substance with an unsaturated carboxylic acid or the derivativethereof and an unsaturated aromatic monomer in the optional co-presenceof a radical initiator, with an extruder, Banbury mixer, kneader, or thelike, usually at a temperature of 200° to 280° C., preferably 230° to260° C. usually for a residence time, which varies depending upon theradical initiator, of 0.2 to 10 minutes.

The presence of too large an amount of oxygen during the kneadingsometimes results in formation of a gel or serious coloring. Therefore,the kneading is carried out desirably in the substantial absence ofoxygen.

When the kneading temperature is lower than 200° C., there are somecases where it is difficult to graft the unsaturated carboxylic acidanhydride in such an amount as desired, and the effect on improvement inthe degree of the graft reaction tends to be small. When the kneadingtemperature is higher than 280° C., the effect on improvement in thedegree of the graft reaction tends to be small, and undesirably in somecases, formation of a gel, coloring, etc., are liable to occur.

The kneading machine for the modification is not critical. Usually, anextruder is preferred since it permits continuous production, and morepreferred is an extruder having a single screw or twin screw suitablefor homogeneously kneading the starting materials.

In order to remove unreacted components (an unsaturated carboxylic acidor the derivative thereof, an unsaturated aromatic monomer, a radicalinitiator, etc.) and by-products such as oligomers and decompositionproducts thereof from the reaction product, the reaction product can bepurified by effecting vacuum pump-suction through vent lines halfwayalong the extruder or in a place near its outlet, or alternatively bydissolving the reaction product in a suitable solvent to precipitate it.The reaction product can be also subjected to heat treatment at atemperature of not less than 60° C and vacuuming while it is in a moltenstate.

The above three or four components may be separately fed to a kneadingmachine, or alternatively, some or all of these components may beuniformly mixed in advance of feeding them. Example, it is possible toemploy a kneading method which comprises preliminarily impregnating arubber with both a radical initiator and an unsaturated aromaticmonomer, feeding the resulting rubber and an unsaturated carboxylic acidor the derivative thereof to an extruder at the same time and kneadingthe resultant mixture. It is also possible to employ a modificationmethod which comprises feeding a radical initiator and/or an unsaturatedcarboxylic acid or the derivative thereof and an unsaturated aromaticmonomer halfway along an extruder.

A variety of additives may be optionally added to the modified rubberysubstance (I) during the modification or post-treatment. Examples ofsuch additives are antioxidants, heat stabilizers, light stabilizers,nucleating agents, lubricants, antistatic agents, inorganic or organiccolorants, rust preventives, crosslinking agents, foaming agents,plasticizers, fluorescent agents, surface treating agents, surfacebrighteners, etc.

The unsaturated carboxylic acid or the derivative thereof and radicalinitiator to obtain the modified rubbery substance (I) can be selectedfrom those compounds used for the production of the modifiedpolypropylene (A), etc. As an unsaturated aromatic monomer, styrene ismost preferred. The unsaturated aromatic monomer can be also selectedfrom o-methylstyrene, p-methylstyrene, α-methylstyrene, vinyltoluene anddivinylbenzene. These may be used in combination.

In the production of the modified rubbery substance (I), the unsaturatedaromatic monomer is used to prevent gel formation and improve the graftreaction degree. Per 100 parts by weight of the starting rubberysubstance, the amount of the unsaturated aromatic monomer is preferably0.2 to 20 parts by weight, and the amount of the unsaturated carboxylicacid or the derivative thereof is preferably 0.5 to 15 parts by weight.When the unsaturated aromatic monomer is also used, the amount of theunsaturated carboxylic acid or the derivative thereof is preferably 0.5to 15 parts by weight, and the weight ratio of the unsaturated aromaticmonomer to unsaturated carboxylic acid or the derivative thereof ispreferably 0.1 to 3.0, more preferably 0.5 to 2.0.

When the weight ratio of the unsaturated aromatic monomer to theunsaturated carboxylic acid or the derivative thereof is less than 0.1,there are some cases where no effect is observed on prevention of gelformation and improvement in the graft reaction degree. Even when theabove weight ratio exceeds 3.0, there are some cases where no furthereffect can be expected.

The amount used of the radical initiator depends on its kind andkneading conditions. In general, it can be used in an amount of 0.005 to1.0 part by weight, preferably 0.01 to 0.5 part by weight per 100 partsby weight of the rubber as a starting rubber material. When the amountof the radical initiator is less than 0.005 part by weight, there aresome cases where the unsaturated carboxylic acid or the derivativethereof is not grafted in an amount as described, and the effect ofcombined use of the unsaturated aromatic monomer on an increase in anamount of the grafted unsaturated carboxylic acid or the derivativethereof is sometimes small. When the above amount exceeds 1.0 part byweight, gel formation is, undesirably, liable to occur.

The modified rubbery substance (I) obtained above generally contains 0.1to 5% by weight of the grafted unsaturated carboxylic acid or thederivative thereof and preferably contains 0.1 to 5% by weight of thegrafted unsaturated aromatic monomer. The Mooney viscosity (ML₁₊₄ 121°C.) thereof is preferably 5 to 120.

The modified rubbery substance (I) is also produced by another method inwhich the unsaturated carboxylic acid or the derivative thereof isintroduced into the main chain of the starting rubber material bycopolymerization in the presence of a polymerization initiator and acatalyst. In general, the modified rubbery substance can be produced bythe following known high-pressure radical copolymerization method. Thatis, it can be produced by copolymerizing ethylene and aradical-polymerizable monomer (comonomer) in the presence of a freeradical-generating agent such as organic peroxide, oxygen, etc. Thecopolymerization is usually carried out at a polymerization temperatureof 130° to 300° C. under a polymerization pressure of 500 to 3,000kg/cm2.sup..

The radical-copolymerizable monomer can be selected from unsaturatedcarboxylic acids such as acrylic acid, methacrylic acid, etc. oresterification products thereof, vinyl esters such as vinyl acetate,etc., and the like. Specific examples of the esterification products ofunsaturated carboxylic acids are methyl acrylate, ethyl acrylate, methylmethacrylate, glycidyl methacrylate, etc. These comonomers can be usedalone or in combination.

The comonomer content in the modified rubbery substance (I) directlycopolymerized is usually 0.1 to 40% by weight, preferably 1 to 35% byweight. When the comonomer content is less than 0.1% by weight, thereare some cases where no effect of the modification is obtained.

Those specified as examples of the ethylene copolymer rubber of thestarting rubbery substance for the rubbery substance (H) and themodified rubbery substance (I) are excluded from the scope of thesecopolymers. Of these, an ethylene-acrylic acid copolymer and anethylene-methacrylic acid copolymer are preferred.

Each of the modified polypropylene resin compositions (A') and (B') isproduced by co-modifying a polypropylene and a rubbery substance asstarting materials by adding an unsaturated carboxylic acid or thederivative thereof or a mixture of an unsaturated carboxylic acid or thederivative thereof with an unsaturated aromatic monomer.

That is, the modified polypropylene resin compositions (A') and (B') canbe produced according to a similar method to those described concerningthe production of the modified polypropylenes (A) and (B) or themodified rubbery substance (I), respectively. The polypropylene and therubbery substance as starting materials can be co-modified by allowingthem to be co-present and graft-copolymerizing an unsaturated carboxylicacid or the derivative thereof or a mixture of an unsaturated carboxylicacid or the derivative thereof with an unsaturated aromatic monomer tothem optionally in the presence of a radical initiator.

The polypropylene and an ethylene copolymer rubber as starting materialsare allowed to be co-present as follows according to various knownmethods. When these two starting materials are pellets, powders orpulverized products, these materials are fed into an extruder separatelyor through the same feed port to allow them to be co-present in theapparatus, or these materials are preliminarily uniformly mixed by meansof a simple mixing device such as a tumbler, Henschel mixer, etc. Wheneither of these materials is a large solid in a bale form, etc., theyare preliminarily melt-kneaded and homogenized with a batchmelt-kneading apparatus such as a roll, a kneader, a Banbury mixer,etc., and further, pelletized or pulverized so that it ca be easily fedto a co-modifying apparatus.

Steps other than the step of allowing the polypropylene and the rubberysubstance as starting materials to be co,-present can be carried out inthe same manner as those used for the production of the modifiedpolypropylenes (A) and (B) or for the production of the modified rubberysubstance (I), whereby the above materials are co-modified.

In the above co-modification, the proportions of the polypropylene andthe rubbery substance as starting materials can be freely selected.However, it is preferable to determine the proportions thereof in viewof the proportions of the modified polypropylenes (A) and (B) and themodified rubbery substance (I) in the thermoplastic resin composition ofthe present invention.

When the co-modification is carried out, the amount of the unsaturatedcarboxylic acid or the derivative thereof, per 100 parts by weight ofthe polypropylene and the rubbery substance in total, is preferably 0.01to 20 parts by weight, more preferably 0.1 to 5 parts by weight, and theamount of the radical initiator, if necessary, is preferably at most 5parts by weight, more preferably 0.001 to 2 parts by weight.

In order to disperse the polypropylene and the rubbery substance asstarting materials while dynamically co-modifying them, it is preferableto use a highly efficient melt-kneading apparatus such as a highlyefficient twin-screw extruder, etc.

The amount of the unsaturated carboxylic acid or the derivative thereofwhich is grafted on the modified polypropylene compositions (A') and(B') is not critical. It is usually 0.10 to 0.50% by weight, preferably0.20 to 0.45% by weight. As the unsaturated carboxylic acid or thederivative thereof, maleic anhydride is preferred. The melt flow rate ofeach of the modified polypropylene compositions (A') and (B') is notcritical. It is usually 0.1 to 100 g/minute, preferably 5 to 50 g/10minutes. The amount of the unsaturated aromatic monomer grafted in themodified polypropylene composition (B') is not critical. It is usuallyless than 0.5% by weight, preferably 0.1 to 0.3% by weight. As anunsaturated aromatic monomer, styrene is preferred.

In thermoplastic resin composition of the present invention, one ofpreferred embodiments is a composite material which is obtained byfurther incorporating thereinto a flame-retardant or flame retardantauxiliary, a lubricant, a nucleating agent, a plasticizer, a dye, apigment, an antistatic agent, an antioxidant, a weatherability-impartingagent, etc.

In the thermoplastic resin composition of the present invention, theresin composition (F) usually contains 1 to 99% by weight, preferably 5to 95% by weight of the modified polypropylene-based resin composition(D) or (D') as a first component. When the above content is less than 1%by weight, there are some cases where the resultant thermoplastic resincomposition is not sufficient in moldability, toughness, waterresistance, chemical resistance, etc.

When the modified polypropylene-based resin composition (D) or (D') is amixture composition of either the modified polypropylenes (A) or (B) anda polypropylene (C) or a mixture composition of either the modifiedpolypropylene compositions (A') or (B') and a polypropylene (C), thecontent of the modified polypropylene (A) or (B) or the content of themodified polypropylene composition (A') or (B') in the composition ispreferably not less than 5% by weight. When this content is less than 5%by weight, the final resin composition tends to have a problem incompatibility and dispersibility, and it is sometimes difficult toobtain sufficient toughness and impact resistance. The improvement inthe coatability and printability tends to be insufficient, either.

The resin composition (F) contains 99 to 1% by weight, preferably 95 to5% by weight, more preferably 80 to 5% by weight of the thermoplasticcopolymer (E) containing an acid anhydride moiety of six-membered ring.The thermoplastic copolymer (E) containing an acid anhydride moiety ofsix-membered ring produces an effect on improvement in heat resistance,stiffness, etc. When the amount of the thermoplastic copolymercontaining an acid anhydride moiety of six-membered rings less than 1%by weight, no desirable effect can be obtained on the heat resistance,stiffness, etc. When this amount exceeds 99% by weight, undesirably, theresultant thermoplastic resin composition shows a low impact resistanceand fluidity, and its specific gravity increases.

The amount of the epoxy group-containing copolymer (G), per 100 parts byweight of the thermoplastic composition (F) consisting of the modifiedpolypropylene resin-based composition (D) or (D') and the thermoplasticcopolymer containing an acid anhydride moiety of six-membered ring, is0.1 to 300 parts by weight, preferably 1 to 200 parts by weight. Whenthis amount is less than 0.1 part by weight, the resulting resincompositions causes problems on compatibility and dispersibility, andthe resultant thermoplastic resin composition is insufficient intoughness and impact resistance and poor in extrusion stability. When itis more than 100 parts by weight, the resultant thermoplastic resincomposition is useful as a thermoplastic elastomer, but when it is morethan 300 parts by weight, the resultant thermoplastic resin compositionshows a considerable decrease in toughness, heat resistance, etc., andno desirable result is obtained.

The amount of the rubbery substance (H) and/or the modified rubberysubstance (I) used to improve the low-temperature impact resistance is0.1 to 300 parts by weight, preferably 1 to 200 parts by weight per 100parts by weight of the resin composition (F) consisting of the modifiedpolypropylene-based resin composition (D) or (D') and the thermoplasticcopolymer (E) containing an acid anhydride moiety of six-membered ring.When this amount is less than 0.1 part by weight, no effect is producedon the improvement in impact resistance. When it is more than 100 partsby weight, the resultant thermoplastic resin composition is useful as athermoplastic elastomer, but when it is more than 300 parts by weight,the resultant thermoplastic resin composition shows a considerabledecrease in toughness, heat resistance, etc., and no desirable result isobtained.

The amount of the basic compound (J) optionally used as a reactionpromoter is not more than 5 parts by weight, preferably 0.01 to 2 partsby weight per 100 parts by weight of the resin composition (F)consisting of the modified polypropylene-based resin composition (D) or(D') and the thermoplastic copolymer (E) containing an acid anhydridemoiety of six-membered ring. When the kneading strength at a kneadingtime is sufficient and when the residence time within a kneader issufficient to the reaction, it is not necessary to incorporate the basiccompound (J). When more than 5 parts by weight of the basic compound (J)is incorporated, the reaction promotion effect is high. However,problems on an appearance of the resultant molded article and offensiveodor tend to be serious due to bleeding, etc., and there are some caseswhere no desirable effect can be obtained.

The process for the production of the thermoplastic resin composition ofthe present invention is not critical, and conventionally knownprocesses can be employed.

It may be effective to employ a process which comprises mixing the resincomponents in a solution state and evaporating a solvent orprecipitating the resin composition in a non-solvent. From an industrialviewpoint, it is actually preferred to employ a process which compriseskneading the resin components in a molten state. The melt-kneading canbe carried out by means of a variety of kneading apparatus such as aBanbury mixer, an extruder, a roll, a kneader, etc.

When the resin components are kneaded, it is preferable to preliminarilymix them all in a powder or pellet form uniformly with an apparatus suchas a tumbler or a Henschel mixer. If necessary, however, it is possibleto individually feed predetermined amounts of the resin components to akneading apparatus without the preliminary mixing.

When a powder or a master batch of the basic compound (J) is used forreaction promotion, any one of the above methods can be adopted. Whenthe basic compound (J) is a liquid, it is preferred to preliminarily mixthe basic compound with the resin components by means of a tumbler or aHenschel mixer. Further, it is also possible to employ a method in whicha kneading apparatus is provided with a quantitative pump and theliquids are added through a tube.

The kneaded resin composition is molded by various molding methods suchas injection molding, extrusion molding, etc. The articles made of thethermoplastic resin composition of the present invention also includesarticles obtained by a method for producing a molded article, whichcomprises dry-blending the starting materials at the time of injectionmolding or extrusion molding without carrying out a preliminary mixingstep, and directly kneading the resultant composition during meltprocessing.

In the present invention, the kneading order is not critical. Some ofits embodiments are shown below.

(1) The modified polypropylene (A) or the modified polypropylenecomposition (A'), the polypropylene (C), the thermoplastic copolymer (E)containing an acid anhydride moiety of six-membered ring, the epoxygroup-containing copolymer (G), the rubbery substance (H) and/or themodified rubbery substance (I), and optionally, the basic compound (J)are kneaded in one lot.

(2) The modified polypropylene-based resin composition (D) or (D') ispreliminary prepared by kneading the modified polypropylene (A) and thepolypropylene (C), or the modified polypropylene composition (A') andthe polypropylene (C). Thereafter, the thermoplastic copolymer (E)containing an acid anhydride moiety of six-membered ring, the epoxygroup-containing copolymer (G), the rubbery substance (H) and/or themodified rubbery substance (I) and optionally the basic compound (J) areincorporated, and the resultant mixture is kneaded.

(3) The modified polypropylene-based resin composition (D) or (D') andthe thermoplastic copolymer (E) containing an acid anhydride moiety ofsix-membered ring are preliminarily kneaded. Thereafter, the epoxygroup-containing copolymer (G), the rubbery substance (H) and/ormodified rubbery substance (I) and optionally the basic compound (J) areincorporated, and the resultant mixture is kneaded. Besides the abovemethods, other kneading orders may be possible. However, when themodified polypropylene (A) or the modified polypropylene composition(A') and the epoxy group-containing copolymer (G) are preliminarilykneaded, when the epoxy group-containing copolymer (G) and the modifiedrubbery substance (I) are preliminary kneaded, or when the thermoplasticcopolymer (E) containing an acid anhydride moiety of six-membered ringand the epoxy group-containing copolymer (G) are preliminarily kneaded,a gel is sometimes formed depending upon proportions of these twocomponents. In such a case, it is necessary to select suitableproportions of these two components properly before kneading them.

In order to simplify the kneading step, the step for preliminarilyproducing the modified polypropylene composition (A') or (B') may beintegrated into the step for kneading the thermoplastic resincomposition of the present invention.

That is, the thermoplastic resin composition of the present inventionmay be produced by a process comprising the first step of co-modifying apolypropylene and a rubbery substance as starting materials, and thesecond step of charging the polypropylene (C), the thermoplasticcopolymer (E) containing an acid anhydride moiety of six-membered ring,the epoxy group-containing copolymer (G) and optionally the basiccompound (J) to a site where the co-modified components are in a moltenstate.

In order to produce the thermoplastic resin composition of the presentinvention more effectively, it is preferred to use a highly efficienttwin-screw extruder having a high L/D ratio and two or more feed ports.That is, the materials for the co-modification are charged through afirst feed port, and sufficiently co-modified until other componentsthan the modified polypropylene composition (A') or (B') are chargedthrough a next feed port, and then, the other components are chargedthrough a second feed port to knead the resultant mixture, whereby thecomposition can be efficiently produced.

The modified polypropylenes (A) and (B) can be also produced in the samemanner as above.

In order to allow further improve the physical properties of thethermoplastic resin composition of the present invention, a variety ofkneading methods can be employed. For example, in order to obtain anexcellent impact resistance, it is possible to employ a methodcomprising kneading a portion of the epoxy group-containing copolymer(G) with the thermoplastic copolymer (E) containing an acid anhydridemoiety of six-membered ring and incorporating the remaining componentsthereto. In order to obtain an efficient reaction promotion effect ofthe basic compound (J), it is possible to employ a method comprisingdispersing a high concentration of the basic compound (J) in onecomponent which constitutes the thermoplastic resin composition of thepresent invention or a resin which is compatible with the thermoplasticresin composition, and incorporating the resultant master batch into theother components and kneading the resulting mixture.

The thermoplastic resin composition of the present invention can easilygive a molded article by molding it according to a conventional moldingor forming method such as injection molding, extrusion molding,compression molding, blow molding, roll molding, lamination molding,vacuum forming, pressure molding, or the like. The present inventionalso includes the articles obtained by a method for producing a moldedarticle, which comprises dry-blending the above components at the timeof injection molding or extrusion molding without carrying out thepreliminary mixing step, and directly kneading the resultant compositionduring melt processing.

Of the above molding and forming methods, injection molding is preferredfrom the viewpoint of productivity, etc. A molded article is obtained bypreliminarily drying a pelletized composition in a vacuum dryer, a hotair dryer, etc., and injection-molding the composition underpredetermined conditions including injection rate, injection time,cooling temperature, etc.

Molded articles produced from the thermoplastic resin composition of thepresent invention are used as automobile parts, electric and electronicparts, etc. Examples of the automobile parts are exterior fittings suchas a bumper, a fender, an apron, a hood panel, a facia, a locker panel,a locker panel reinforce, a floor panel, a rear quarter panel, a doorpanel, a door support, a roof top, a trunk lid, etc., interior fittingssuch as a instrumental panel, a console box, a glove box, a shift knob,a pillar garnish, a door trim, a steering wheel, an arm rest, a windowroover, a carpet, a head rest, a seat belt, a seat, etc., internalfittings in an engine room such as a distributor cap, an air cleaner, aradiator tank, a battery case, a radiator shroud, a washer tank, acooling fan, a heater case, etc., a mirror body, a wheel cover, a trunktrim, a trunk mat, a gasoline tank, and the like.

Of the above molded articles used as an automobile part, thethermoplastic resin composition of the present invention is particularlysuitably usable for a bumper and a fender of which excellent stiffnessand low-temperature impact resistance are required.

The present invention will be explained hereinafter by reference toExamples, which exemplifies the present invention but shall not limitthe present invention.

Methods for measuring the physical properties in Examples are asfollows.

(1) Melt flow rate

Measured according to the method specified in JIS K 6758. Themeasurement temperature was 230° C., and the load was 2.16 kg unlessotherwise specified.

(2) Tensile test

Carried out according to the method specified in ASTM D638. A test piecehaving a thickness of 3.2 mm was measured for a tensile yield strengthand a tensile elongation. The measurement temperature was 23° C. unlessotherwise specified.

(3) Flexural test

Carried out according to the method specified in JIS K 7203. A testpiece having a thickness of 3.2 mm was measured for a flexural modulusand a flexural strength at a span length of 50 mm at a loading rate of1.5 mm/minute. The measurement temperature was 23° C. unless otherwisespecified. When the test was carried out at a temperature other than 23°C., a sample was conditioned in a constant-temperature bath at apredetermined temperature for 30 minutes before the measurement.

(4) Izod impact strength

Measured according to the method specified in JIS K 7110. A test piecehaving a thickness of 3.2 mm was measured for a notched impact strength.The measurement temperature was 23° C. unless otherwise specified. Whenthe measurement was carried out at a temperature other than 23° C., asample was conditioned in a constant-temperature bath at a predeterminedtemperature for 2 hours before the measurement.

(5) Penetration impact strength

A high rate impact tester (RIT-8000), supplied by Rheometric Inc. (USA))was used. A deformation degree and stress of a flat test piece having athickness of 3 mm were detected by fixing the test piece with a 2-inchcircular holder and hitting a 5/8-inch impact probe (tip sphericalsurface: 5/16 inch radius) against the test piece at a rate of 3m/second, thereby to draw a curve as shown in FIG. 1. The penetrationimpact strength was evaluated by integrating the area along the curve.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 shows one example of measurement charts in evaluation ofpenetration impact strength, in which the abscissa axis indicates adisplacement amount (D: mm) showing deformation of the test piece andthe ordinate axis indicates a stress (N: newton) to the displacementamount. Both of these values were continuously detected and continuouslyplotted in an X-Y plotter whereby said measurement chart was obtained.

A yield point energy was obtained by integrating areas of thedeformation amount and the stress from a start of stress detection to ayield point of a material, and a total energy was obtained byintegrating areas of the displacement amount and the stress from a startportion to a breaking point.

The fracture state of a material was determined to be ductile fracture(D) or brittle fracture (B) by observing a test piece actually subjectedto a fracture test.

An energy value required for yield of a material was evaluated in termsof energy at a yield point, and an energy value required for fracture ofa material was evaluated in terms of total energy. These values areexpressed in a unit of joule (J).

A sample was conditioned in a constant-temperature bath attached to theapparatus. A test piece was placed in the constant temperature bathadjusted to a predetermined temperature and conditioned for 2 hoursbefore the above test. The predetermined temperature was used as ameasurement temperature.

(6) Heat distortion temperature

Measured according to the method specified in JIS K 7207. The fiberstress was measured at 4.6 kg/cm².

(7) Rockwell hardness

Measured according to the method specified in HIS K 7207. The thicknessof a test piece was 3.2 mm, R was used as a steel ball, and theevaluation value was expressed on R scale.

(8) Graft amount of maleic anhydride and styrene

The graft amount of maleic anhydride on each of the modifiedpolypropylenes (A) and (B) and the modified polypropylene compositions(A') and (B') was determined by dissolving a small amount of a sample inhot xylene, forming a precipitate with anhydrous acetone to purify thesample, then redissolving the purified sample in xylene, and titratingthe resultant solution with a methanol solution of NaOH while thesolution was under heat (110° to 120° C.) and phenolphthalein was usedas an indicator.

The graft amount of the maleic anhydride in the modified rubberysubstance (I) was determined by dissolving a small amount of a sample intoluene, forming a precipitate with anhydrous acetone to purify thesample, then redissolving the purified sample in toluene, and titratingthe resultant solution with an ethanol solution of KOH while thesolution was under heat (85° C.) and phenolphthalein was used as anindicator.

The graft amount of styrene was determined on the basis of intensity ofan absorption peak derived from substituted benzene rings observed in aninfrared absorption spectrum of the above purified sample.

(9) Mooney viscosity

Measured according to the method specified in JIS K 6300. Themeasurement temperature was 121° C.

(10) Number average molecular weight

Measured by gel permeation chromatography (GPC) under the followingconditions.

GPC: type 150C, supplied by Waters.

Column: Shodex 80 MA, supplied by Showa Denko K.K.

Sample amount: 300μl (polymer concentration: 0.2 wt%)

Flow rate: 1 ml/min.

Temperature: 135° C.

Solvent: Trichlorobenzene

A calibration curve for calculation of the number average molecularweight was prepared by a conventional method using standard polystyrenesupplied by Tohsoh Corp. A data processor CP-8 Model III supplied byTohsoh Corp. was used for data processing.

(11) Ethylene content

The ethylene content was determined by preparing a press sheet,measuring it for an infrared absorption spectrum, and using acalibration curve from absorbances of characteristic absorptions ofmethyl (--CH₃) and methylene (--CH₂ --) which were observed in theinfrared absorption spectrum.

Referential Example 1 Preparation of modified polypropylene (1) M-PP-1

A modified polypropylene (A) was prepared in the following manner. Apropylene homopolymer, as a starting material, prepared by a slurrypolymerization method according to the process described inJP-A-60-28405, which had a melt flow rate of 1.3 g/10 minutes, anintrinsic viscosity, measured in tetralin at 135° C., of 2.45 dl/g, a20° C. cold xylene soluble of 2.9% by weight, a boiling heptane solubleof 6.7% by weight, and an isotactic pentad, in its boilingheptane-insolubee portion, of 0.952 was modified in the followingmanner.

100 Parts by weight of the propylene homopolymer as a starting material,1.0 part by weight of maleic anhydride, 0.6 part by weight of a radicalinitiator prepared by allowing a propylene homopolymer to support 8% byweight of 1,3-bis(t-butylperoxyisopropyl)benzene (Sanperox®-TYl.3supplied by Sanken Kako Co., Ltd.) and 0.1 part by weight of Irganox®1010 (supplied by Ciba Geigy Ltd.) as a stabilizer were uniformly mixedwith a Henschel mixer. The resultant mixture was melt-kneaded with atwin-screw extruder, model TEX 44 SS-30BW-2V supplied by Japan SteelWorks Ltd., at a temperature of 220° C. for an average residence time of1.5 minutes to give a maleic anhydride-modified polypropylene (A) havinga maleic anhydride graft amount of 0.08% by weight and a melt flow rateof 36 g/10 minutes. This modified polypropylene (A) is abbreviated asM-PP-1 hereinafter.

(2) MS-PP-1

A modified polypropylene (B) was prepared as follows. A propylenehomopolymer, as a starting material, prepared by a slurry polymerizationmethod according to the process described in JP-A-60-28405, which hadthe same structure as that in the above item (1) except for an isotacticpentad of 0.955, was modified in the same manner as in the above item(1) except that 0.5 part by weight of styrene was used in addition,whereby there was obtained a maleic anhydride- and styrene-modifiedpolypropylene (B) having a maleic anhydride graft amount of 0.15% byweight, a styrene graft amount of 0.07% by weight and a melt flow rateof 21 g/10 minutes. This modified polypropylene (B) is abbreviated asMS-PP-1 hereinafter.

(3) MS-PP/EPR-1

A polypropylene and a rubbery substance were co-modified in thefollowing manner. The same polypropylene as that used in the above item(1) was used in an amount of 77% by weight as a starting material, and23% by weight of a pulverized ethylene-propylene copolymer rubber havinga number average molecular weight of 55,000 and an ethylene content of47% by weight was used as the rubbery substance.

The procedure as in the above item (1) was repeated except for the useof 1.5 parts by weight of maleic anhydride, 0.5 part by weight ofstyrene and 0.6 part by weight of a radical initiator per 100 parts byweight of the polypropylene as a starting material and theethylene-propylene copolymer rubber in total, whereby there was obtaineda co-modified polypropylene/rubbery substance having a maleic anhydridegraft amount of 0.18% by weight, a styrene graft amount of 0.1% byweight and a melt flow rate of 11 g/10 minutes.

This co-modified polypropylene/rubbery substance is abbreviated asMS-PP/EPR-1 hereinafter.

(4) MS-PP/EPR-2

The same procedure for the production of a co-modifiedpolypropylene/rubbery substance as in Referential Example 1-(3) wasrepeated except that the amounts of the polypropylene and rubberysubstance as starting materials were changed to 69% by weight and 31% byweight, respectively, whereby there was obtained a co-modifiedpolypropylene/rubbery substance having a maleic anhydride graft amountof 0.21% by weight, a styrene graft amount of 0.12% by weight and a meltflow rate of 9 g/10 minutes. This co-modified polypropylene/ rubberysubstance is abbreviated as MS-PP/EPR-2 hereinafter.

(5) MS-PP/EPR-3

The same procedure for the production of a co-modifiedpolypropylene/rubbery substance as in Referential Example 1-(3) wasrepeated except that an ethylene-butene-1 copolymer rubber having anumber average molecular weight of 50,000 and an ethylene content of 82%by weight was used as a starting rubber substance in place of that usedin Referential Example 1-(3), whereby there was obtained a co-modifiedpolypropylene/rubbery substance having an maleic anhydride graft amountof 0.25% by weight, a styrene graft amount of 0.15% by weight and a meltflow rate of 11 g/10 minutes. This co-modified polypropylene/rubberysubstance is abbreviated as MS-PP/EPR-3 hereinafter.

(6) MS-PP/SEBS-1

The same procedure for the production of a co-modifiedpolypropylene/rubbery substance as in Referential Example 1-(3) wasrepeated except that a styrene-ethylene-butylene block copolymer havinga number average molecular weight of 85,000, a styrene block of whichthe number average molecular weight was 50,000, an ethylene-styreneblock of which the number average molecular weight was 35,000 and astyrene/ethylenebutylene block weight ratio of 30/70 (KRATON®-G 1657,supplied by Shell Chemical) was used as a rubbery substance in place ofthat used in Referential Example 1-(3), whereby there was obtained aco-modified polypropylene/rubbery substance having maleic anhydridegraft amount of 0.20% by weight and a melt flow rate of 13.1 g/10minutes.

This co-modified polypropylene/rubbery substance is abbreviated asMS-PP/SEBS-4 hereinafter.

Referential Example 2 Preparation of modified rubbery substance

A modified rubbery substance (I) was prepared in the following manner.100 Parts by weight of pellets of an ethylene-propylene copolymer rubberhaving a number average molecular weight of 60,000 and an ethylenecontent of 78% by weight, 2.0 parts by weight of maleic anhydride, 2.0parts by weight of styrene and 1.0 part by weight of a radical initiatorprepared by allowing a propylene homopolymer to support 8% by weight of1,3-bis(t-butylperoxyisopropyl)benzene (Sanperox®-TYl.3 supplied bySanken Kako Co., Ltd.) were mixed with a Henschel mixer, and theresultant mixture was melt-kneaded in a twin-screw extruder, TEX 44 SS30BW-2V, supplied by Japan Steel Works Ltd., under a nitrogen atmosphereat a kneading temperature of 250° C. and an extrusion rate of 18 kg/hourto give a modified ethylene-propylene copolymer rubber having a maleicanhydride graft amount of 1.5% by weight, a styrene graft amount of 0.8%by weight and a Mooney viscosity (ML₁₊₄ 121° C.), at 121° C., of 70.This modified ethylenepropylene copolymer rubber is abbreviated asMS-EPM-1 hereinafter.

Referential Example 3 Preparation of thermoplastic copolymer containingan acid anhydride moiety of six-membered ring

2.2 Liters of pure water and 2.4 g of hydroxycellulose were charged intoa 5-liter autoclave having a stirrer, and dissolved. Thereafter, aprescribed amount of the monomers shown in Table 1, 6.4 g of laurylmercaptan and 5.6 g of lauroyl peroxide were added, and the resultantmixture was polymerized at 80° C. for 1 hour and 40 minutes and furtherat 100° C. for 1 hour. And, the reaction mixture was washed, dehydratedand dried to give a particulate polymer.

100 Parts by weight of the above particulate polymer was mixed with 0.02part by weight of sodium hydroxide with a Henschel mixer and theresultant mixture was granulated with an extruder equipped with a venthaving a diameter of 40 mm (VS40-28, supplied by Tanabe PlasticMachinery) at a screw rotation rate of 50 rpm at a resin temperature of290° C. to give colorless transparent pellets.

Table 1 shows melt flow indices and compositions of the pellets andphysical properties of the articles obtained by injection-molding thepellets.

(1) Composition distribution of copolymer (i)(A) Copolymer

The amount of an acid anhydride moiety of six-membered ring isquantitatively determined by means of absorption at 1,760 cm⁻¹ inherentto the acid anhydride structure.

The amount of an unreacted methacrylic acid is calculated by deductingthe amount of an acid anhydride moiety of six-membered ring from theamount of methacrylic acid charged.

The amounts of styrene and methyl methacrylate are calculated on thebasis of charged amount ratios.

(2) Melt flow index (MI)

Measured according to ASTM D-1238 at 230° C. under a load of 3.8 kg.

(3) Physical properties of molded articles (i) Method for preparation oftest piece

A pelletized polymer was injection-molded with an injection moldingmachine (M140-SJ, supplied by Meiki Seisakusho) at an injection pressureof 80 kg/cm² and a resin temperature of 260° C.

(ii) Heat resistance

Measured for a heat deformation temperature (HDT) (° C.) according toASTM D648.

The measurement was conducted at a fiber stress of 18.6 kg/cm² after amolded article had been annealed for 12 hours.

Referential Example 4 Preparation of epoxy group-containing copolymer(1) E-MA-GMA-1

An epoxy group-containing copolymer (F) was prepared in the followingmanner. A terpolymer having a melt flow rate of 21 g/10 minutes (at 190°C., load: 2.16 kg) and having a weight ratio among ethylene, methylmethacrylate and glycidyl methacrylate of 65 : 15 : 20 (% by weight) wasprepared by a high-pressure radical polymerization method according tothe process described in JP-A-47-23490 and JP-A-48-11888.

This epoxy group-containing copolymer is abbreviated as E-MA-GMA-1hereinafter.

(2) E-VA-GMA-1

An epoxy group-containing copolymer (G) was prepared in the same manneras in Referential Example 4-(1). The resultant terpolymer had a weightratio among ethylene, vinyl acetate and glycidyl methacrylate of 85 : 5: 10 (% by weight) and a melt flow rate of 7 g/10 minutes (at 190° C.,load: 2.16 kg). This epoxy group-containing copolymer is abbreviated asE-VA-GMA-1 hereinafter.

Example 1 and Comparative Example 1

Each of the components obtained in the manner shown in ReferentialExamples were mixed in the proportions shown in Table 2 andpreliminarily mixed with a Henschel mixer. Then, the resultant mixturewas melt-kneaded in a continuous twin-screw extruder having a tripleflighted rotor and a kneading disk in each of two kneading zones ofwhich one is located at a zone next to a first feed port and the otherat a zone next to a second feed port (TEX 44 SS 30BW-2V, supplied byJapan Steel Works Ltd.) at an extrusion rate of 30 kg/hour at a resintemperature of 240° C. and a screw revolution rate of 350 rpm undervacuuming through vent holes, whereby a composition was obtained.

The above composition was dried with a hot air dryer at 120° C. for 2hours, and injection-molded with an injection molding machine, IS150E-Vsupplied by Toshiba Machinery, at a molding temperature of 240° C. at amold cooling temperature of 70° C. for an injection time of 15 secondsand a curing time of 30 seconds, whereby test pieces for evaluation wereobtained.

The test pieces were evaluated on its physical properties according tothe predetermined methods. Table 3 shows the results.

Table 3 shows that, as compared with the test piece obtained inComparative Example 1 which piece contains no epoxy group-containingcopolymer, the test piece of the present invention obtained in Example 1has a remarkably improved Izod impact strength and penetration impactstrength.

Examples 2-12 and Comparative Examples 2-5

A modified polypropylene obtained in the manner described in ReferentialExamples, a thermoplastic copolymer containing an acid anhydride moietyof six-membered ring, an epoxy-group containing copolymer and a modifiedrubbery substance were mixed in the proportions shown in Table 2, and acomposition was obtained in the same manner as in Example 1. Test pieceswere prepared in the same manner as in Example 1, and the test pieceswere evaluated on their physical properties in the same manner as inExample 1. Table 3 shows the results.

Example 13

The same materials as in Example 3 and benzyldimethylamine (Sumicure®BD,supplied by Sumitomo Chemical Co., Ltd.) as a basic compound (J) whichwas a reaction promoter were mixed in the proportions as shown in Table2, and a composition was obtained in the same manner as in Example 3.Test pieces were prepared in the same manner as in Example 3, and thetest pieces were evaluated on their physical properties in the samemanner as in Example 3. Table 3 shows the results.

The test pieces of the present invention obtained in Example 3, to whichthe basic compound (J) had not been incorporated, showed good physicalproperties. And, the test piece obtained in this Example, to which thebasic compound (J) had been incorporated, has a further improved levelof Izod impact strength and penetration impact strength.

The thermoplastic resin composition according to the present inventionnot only exhibits an excellent processability but also producesremarkable advantages in that it gives highly improved physicalproperties as compared to those expected from each polymer whichconstitutes the thermoplastic resin composition of the presentinvention.

The novel resin composition provided by the present invention can beeasily processed into molded articles, films and sheets by a moldingmethod generally used for thermoplastic resins such as injectionmolding, extrusion molding, etc., and can give products which havewell-balanced properties among stiffness, heat resistance, impactresistance, scratch resistance, coatability, oil resistance, chemicalresistance, water resistance, etc., and which are excellent inappearance uniformity and smoothness. The thermoplastic resincomposition of the present invention is particularly suitable for usewhere well-balanced properties among heat resistance and impactresistance, low-temperature impact resistance in particular, arerequired.

                                      TABLE 1                                     __________________________________________________________________________                                        Physical properties                                                           of molded article                                          Copolymer               Water                                Abbrevi-                                                                            Amount of  composition (wt %)      absorbing                            ation of                                                                            monomer (%)        Acid an-   HDT  capacity                             polymer                                                                             MMA MAA ST MMA MAA hydride                                                                            ST MI (°C.)                                                                       (%)                                  __________________________________________________________________________    PGA-1 1280                                                                              160 160                                                                              80  2   8    10 2.1                                                                              120  1.3                                  PGA-2 1360                                                                              160  80                                                                              85  2   8     5 1.8                                                                              120  1.6                                  PGA-3 1120                                                                              240 240                                                                              70  3   12   15 1.7                                                                              128  1.3                                  PGA-4  720                                                                              320 560                                                                              44  6   16   34 1.5                                                                              135  1.2                                  __________________________________________________________________________     Note:                                                                         MMA: Methyl methacrylate                                                      MAA: Methacrylic acid                                                         ST: Styrene                                                                   Acid anhydride: Acid anhydride moiety of sixmembered ring from methacryli     acid                                                                     

                                      TABLE 2                                     __________________________________________________________________________                     Thermoplastic                                                                 copolymer (E)                                                                 containing acid                                                               anhyride moiety                                                                        Epoxy group -                                                                          Modified Basic                             Component                                                                            Modified  of six-membered                                                                        containing                                                                             rubbery  compound                          No.    polypropylene                                                                           ring     copolymer (G)                                                                          substance (I)                                                                          (J)                               __________________________________________________________________________    Example 1                                                                            MPP-1                                                                              60 wt %                                                                            PGA-1                                                                             20 wt %                                                                            E-MA-                                                                              2 wt %                                                                            MS- 18 wt %                                                                            --                                                          GMA-1    EPM-1                                      Example 2                                                                            M-PP-1                                                                             60   PGA-2                                                                             20   E-MA-                                                                              2   MS- 18   --                                                          GMA-1    EPM-1                                      Example 3                                                                            MS-PP-1                                                                            60   PGA-1                                                                             20   E-VA-                                                                              2   MS- 18   --                                                          GMA-1    EPM-1                                      Example 4                                                                            MS-PP-1                                                                            60   PGA-2                                                                             20   E-VA-                                                                              2   MS- 18   --                                                          GMA-1    EPM-1                                      Example 5                                                                            MS-PP/                                                                             78   PGA-1                                                                             20   E-MA-                                                                              2   --       --                                       EPR-1              GMA-1                                               Example 6                                                                            MS-PP/                                                                             78   PGA-3                                                                             20   E-MA-                                                                              2   --       --                                       EPR-1              GMA-1                                               Example 7                                                                            MS-PP/                                                                             78   PGA-4                                                                             20   E-MA-                                                                              2   --       --                                       EPR-1              GMA-1                                               Example 8                                                                            MS-PP/                                                                             58   PGA-1                                                                             40   E-MA-                                                                              2   --       --                                       EPR-2              GMA-1                                               Example 9                                                                            MS-PP/                                                                             78   PGA-1                                                                             20   E-MA-                                                                              2   --       --                                       EBR-3              GMA-1                                               Example 10                                                                           MS-PP/                                                                             78   PGA-1                                                                             20   E-MA-                                                                              2   --       --                                       SEBS-4             GMA-1                                               Example 11                                                                           MS-PP-1                                                                            78   PGA-1                                                                             20   E-VA-                                                                              2   --       --                                                          GMA-1                                               Example 12                                                                           MS-PP-1                                                                            55   PGA-1                                                                             40   E-VA-                                                                              5   --       --                                                          GMA-1                                               Example 13                                                                           MS-PP-1                                                                            60   PGA-1                                                                             20   E-VA-                                                                              2   MS- 18   Sumicure ®                                              GMA-1    EPM-1    BD 0.5 part                       Comparative                                                                          MS-PP-1                                                                            60   PGA-1                                                                             20   --       MS- 20   --                                Example 1                          EPM-1                                      Comparative                                                                          MS-PP-1                                                                            60   PGA-1                                                                             20   --       MS- 20   --                                Example 2                          EPM-1                                      Comparative                                                                          MS-PP-1                                                                            80   PGA-1                                                                             20   --       --       --                                Example 3                                                                     Comparative                                                                          MS-PP-1                                                                            60   PGA-1                                                                             40   --       --       --                                Example 4                                                                     Comparative                                                                          MS-PP-1                                                                            90   --       E-VA-                                                                              10  --       --                                Example 5                 GMA-1                                               __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________                 Tensile                                                                       properties                                                                              Flexural            Penetration                                     Strength                                                                           Elonga-                                                                            properties                                                                              Izod impact                                                                             impact strength                                                                       Heat                              Melt flow                                                                           at yield                                                                           tion at                                                                            Elastic   strength  (YE/TE)*.sup.1                                                                        deformation                                                                          Rockwell            Physical                                                                             rate (g/10                                                                          point                                                                              break                                                                              modulus                                                                            Strength                                                                           23° C.                                                                      -30° C.                                                                     -30° C.                                                                        temperature                                                                          hardness            properties                                                                           (minutes)                                                                           (kg/cm.sup.2)                                                                      (%)  (kg/cm.sup.2)                                                                      (kg/cm.sup.2)                                                                      (kg · cm/cm)                                                                   (J: joul)                                                                             (° C.)                                                                        H.sub.R             __________________________________________________________________________    Example 1                                                                            13.0  187  >200 10,700                                                                             259  20   8.9  24/30 (D-B)                                                                           114    66                  Example 2                                                                            9.7   184  150  10,500                                                                             256  18   7.8  21/28 (D-B)                                                                           116    66                  Example 3                                                                            10.6  199  >200 11,300                                                                             276  22   9.0  24/31 (D-B)                                                                           115    67                  Example 4                                                                            8.0   196  140  11,000                                                                             274  20   7.9  22/29 (D-B)                                                                           118    67                  Example 5                                                                            12.1  204  >200 10,800                                                                             248  27   7.0  25/37 (D-B)                                                                           105    66                  Example 6                                                                            13.2  183  80   11,600                                                                             272  19   4.5  22/25 (B)                                                                             106    66                  Example 7                                                                            11.8  201  50   11,000                                                                             256  25   7.0  28/36 (D-B)                                                                           104    67                  Example 8                                                                            4.6   188  40   11,000                                                                             232  15   5.6  24/26 (B)                                                                             110    56                  Example 9                                                                            11.4  232  140  12,300                                                                             307  18   3.4  20/22 (B)                                                                             109    81                  Example 10                                                                           15.8  177  >200  8,600                                                                             218  25   7.4  30/43 (D-B)                                                                           104    67                  Example 11                                                                           7.3   211  >200 11,500                                                                             288  28   11.4 27/36 (D-B)                                                                           120    73                  Example 12                                                                           12.5  332  60   16,100                                                                             484  6.4  3.4  1.5/2.1 (B)                                                                           119    93                  Example 13                                                                           6.0   426  40   18,700                                                                             590  6.9  3.9  1.9/3.0 (B)                                                                           121    91                  Comparative                                                                          17.8  240  20   12,200                                                                             340  3.2  1.9  0.5/1.3 (B)                                                                           120    73                  Example 1                                                                     Comparative                                                                          12.9  251  20   12,700                                                                             357  3.7  2.0  0.6/1.4 (B)                                                                           121    74                  Example 2                                                                     Comparative                                                                          13.4  390  15   17,900                                                                             551  2.4  1.9  0.1/0.2 (B)                                                                           127    97                  Example 3                                                                     Comparative                                                                          10.1  489  10   23,300                                                                             741  2.0  1.8  0.1/0.2 (B)                                                                           131    98                  Example 4                                                                     Comparative                                                                          18.0  290  20   15,500                                                                             360  4.5  3.0  2.0/3.0 (B)                                                                           120    90                  Example 5                                                                     __________________________________________________________________________     Note:                                                                         *.sup.1 Penetration impact strength                                            YE and TE are short for energy at yield point and total energy,              respectively.                                                                 D and B are short for fracture states of ductile fracture and brittle         fracture, respectively.                                                  

What is claimed is:
 1. A thermoplastic resin composition whichcomprises:(i) 1-99% by weight of at least one member selected from thegroup consisting of(a) a modified polypropylene (A) to which has beengrafted copolymerized an unsaturated carboxylic acid or a derivativethereof, (b) a modified polypropylene (B) to which has been graftcopolymerized an unsaturated aromatic monomer and either an unsaturatedcarboxylic acid or a derivative thereof, (c) a mixture of the modifiedpolypropylene (A) and a polypropylene (C), (d) a mixture of the modifiedpolypropylene (B) and a polypropylene (C), (e) a modified mixture (A')of a polypropylene (C) and a rubbery substance (H) to which mixture hasbeen graft copolymerized an unsaturated carboxylic acid or a derivativethereof, (f) a modified mixture (B') of a polypropylene (C) and arubbery substance (H) to which mixture has been graft copolymerized anunsaturated aromatic monomer and either an unsaturated carboxylic acidor a derivative thereof, (g) a mixture of the modified mixture (A') anda polypropylene (C), and (h) a mixture of the modified mixture (B') anda polypropylene (C), and (ii) 99-1% by weight of a thermoplasticcopolymer (E) containing an acid anhydride six-membered ring moiety, and(2) 0.1 to 300 parts by weight of an epoxy group-containing copolymer(G).
 2. The thermoplastic resin composition of claim 1, wherein theresin composition (F) consists of(i) 1-99% by weight of at least onemodified polypropylene-based resin composition (D) selected from thegroup consisting of(a) a modified polypropylene (A) to which has beengrafted copolymerized an unsaturated carboxylic acid or a derivativethereof, (b) a modified polypropylene (B) to which has been graftcopolymerized an unsaturated aromatic monomer and either an unsaturatedcarboxylic acid or a derivative thereof, (c) a mixture of the modifiedpolypropylene (A) and a polypropylene (C), and (d) a mixture of themodified polypropylene (B) and a polypropylene (C), and (ii) 99-1% byweight of a thermoplastic copolymer (E) containing an acid anhydridesix-membered ring moiety.
 3. The thermoplastic resin composition ofclaim 1, wherein the resin composition (F) consists of(i) 1-99% byweight at least one modified polypropylene-based resin composition (D')selected from the group consisting of(e) a modified mixture (A') of apolypropylene (C) and a rubbery substance (H) to which mixture has beengraft copolymerized an unsaturated carboxylic acid or a derivativethereof, (f) a modified mixture (B') of a polypropylene (C) and arubbery substance (H) to which mixture has been graft copolymerized anunsaturated aromatic monomer and either an unsaturated carboxylic acidor a derivative thereof, (g) a mixture of the modified mixture (A') anda polypropylene (C), and (h) a mixture of the modified mixture (B') anda polypropylene (C), and (ii) 99-1% by weight of a thermoplasticcopolymer (E) containing an acid anhydride six-membered ring moiety. 4.The thermoplastic resin composition of claim 1, wherein the unsaturatedcarboxylic acid or a derivative thereof is maleic anhydride.
 5. Thethermoplastic resin composition of claim 2, wherein the unsaturatedcarboxylic acid or a derivative thereof is maleic anhydride.
 6. Thethermoplastic resin composition of claim 3, wherein the unsaturatedcarboxylic acid or a derivative thereof is maleic anhydride.
 7. Thethermoplastic resin composition of claim 1, wherein the resincomposition (F) consists of(i) 1-99% by weight of at least one memberselected from the group consisting of(b) a modified polypropylene (B) towhich has been graft copolymerized an unsaturated aromatic monomer andeither an unsaturated carboxylic acid or a derivative thereof, (d) amixture of the modified polypropylene (B) and a polypropylene (C), (f) amodified mixture (B') of a polypropylene (C) and a rubbery substance (H)to which mixture has been graft copolymerized an unsaturated aromaticmonomer and either an unsaturated carboxylic acid or a derivativethereof, (h) a mixture of the modified mixture (B') and a polypropylene(C), and (ii) 99-1% by weight of a thermoplastic copolymer (E)containing an acid anhydride six-membered ring moiety.
 8. Thethermoplastic resin composition of claim 7, wherein the resincomposition (F) consists of(i) 1-99% by weight of at least one memberselected from the group consisting of(b) a modified polypropylene (B) towhich has been graft copolymerized an unsaturated aromatic monomer andeither an unsaturated carboxylic acid or a derivative thereof, and (d) amixture of the modified polypropylene (B) and a polypropylene (C), and(ii) 99-1% by weight of a thermoplastic copolymer (E) containing an acidanhydride six-membered ring moiety.
 9. The thermoplastic resincomposition of claim 7, wherein the resin composition (F) consists of(i)1-99% by weight of at least one member selected from the groupconsisting of(f) a modified mixture (B') of a polypropylene (C) and arubbery substance (H) to which mixture has been graft copolymerized anunsaturated aromatic monomer and either an unsaturated carboxylic acidor a derivative thereof, and (h) a mixture of the modified mixture (B')and a polypropylene (C), and (ii) 99-1% by weight of a thermoplasticcopolymer (E) containing an acid anhydride six-membered ring moiety. 10.The thermoplastic resin composition of claim 7, wherein the unsaturatedaromatic monomer is styrene.
 11. The thermoplastic resin composition ofclaim 8, wherein the unsaturated aromatic monomer is styrene.
 12. Thethermoplastic resin composition of claim 9, wherein the unsaturatedaromatic monomer is styrene.
 13. The thermoplastic resin composition ofclaim 10, wherein the unsaturated carboxylic acid or a derivativethereof is maleic anhydride.
 14. The thermoplastic resin composition ofclaim 11, wherein the unsaturated carboxylic acid or a derivativethereof is maleic anhydride.
 15. The thermoplastic resin composition ofclaim 12, wherein the unsaturated carboxylic acid or a derivativethereof is maleic anhydride.
 16. The thermoplastic resin composition ofclaim 1, wherein the thermoplastic copolymer containing an acidanhydride six-membered ring moiety is a thermoplastic copolymerhaving(1) a repeating unit derived from methyl methacrylate, (2) atleast one repeating unit selected from the group consisting of arepeating unit derived from methacrylic acid and a repeating unitderived from acrylic acid, and (3) a repeating unit derived from an acidanhydride of six-membered ring having the formula, ##STR5## wherein Rand R' are independently methyl or hydrogen, the content of therepeating unit (1) in the copolymer being 10 to 95% by weight, thecontent of the repeating units (2) and (3) in the copolymer being 5 to35% by weight, the weight ratio of the repeating unit (3) to therepeating units (2) and (3) being 55 : 100 or more, and the reducedviscosity of the copolymer, when measured at 25° C. with 1 weight%dimethyl formamide solution, being 0.3 to 1.5 dl/g.
 17. Thethermoplastic resin composition of claim 1, wherein the thermoplasticcopolymer containing an acid anhydride six-membered ring moiety is athermoplastic copolymer having(1) a repeating unit derived from methylmethacrylate, (2) at least one repeating unit selected from the groupconsisting of a repeating unit derived from methacrylic acid and arepeating unit derived from acrylic acid, (3) a repeating unit derivedfrom an acid anhydride of six-membered ring having the formula, ##STR6##wherein R and R' are independently methyl or hydrogen, the content ofthe repeating unit (1) in the copolymer being 10 to 95% by weight, thecontent of the repeating unit (4) in the copolymer being at most 55% byweight, the content of the repeating units (2) and (3) in the copolymerbeing 5 to 35% by weight, the weight ratio of the repeating unit (3) tothe repeating units (2) and (3) being 55 : 100 or more, and the reducedviscosity of the copolymer, when measured at 25° C. with 1 weight%dimethyl formamide solution, being 0.3 to 1.5 dl/g.
 18. Thethermoplastic resin composition of claim 2, wherein the thermoplasticcopolymer containing an acid anhydride six-membered ring moiety is athermoplastic copolymer having(1) a repeating unit derived from methylmethacrylate, (2) at least one repeating unit selected from the groupconsisting of a repeating unit derived from methacrylic acid and arepeating unit derived from acrylic acid, and (3) a repeating unitderived from an acid anhydride of six-membered ring having the formula,##STR7## wherein R and R' are independently methyl or hydrogen, thecontent of the repeating unit (1) in the copolymer being 10 to 95% byweight, the content of the repeating units (2) and (3) in the copolymerbeing 5 to 35% by weight, the weight ratio of the repeating unit (3) tothe repeating units (2) and (3) being 55 : 100 or more, and the reducedviscosity of the copolymer, when measured at 25° C. with 1 weight%dimethyl formamide solution, being 0.3 to 1.5 dl/g.
 19. Thethermoplastic resin composition of claim 2, wherein the thermoplasticcopolymer containing an acid anhydride six-membered ring moiety is athermoplastic copolymer having(1) a repeating unit derived from methylmethacrylate, (2) at least one repeating unit selected from the groupconsisting of a repeating unit derived from methacrylic acid and arepeating unit derived from acrylic acid, (3) a repeating unit derivedfrom an acid anhydride of six-membered ring having the formula, ##STR8##wherein R and R' are independently methyl or hydrogen, and (4) arepeating unit derived from an ethylenic α,β-unsaturated monomer,thecontent of the repeating unit (1) in the copolymer being 10 to 95% byweight, the content of the repeating unit (4) in the copolymer being atmost 55% by weight, the content of the repeating units (2) and (3) inthe copolymer being 5 to 35% by weight, the weight ratio of therepeating unit (3) to the repeating units (2) and (3) being 55 : 100 ormore, and the reduced viscosity of the copolymer, when measured at 25°C. with 1 weight% dimethyl formamide solution, being 0.3 to 1.5 dl/g.20. The thermoplastic resin composition of claim 3, wherein thethermoplastic copolymer containing an acid anhydride six-membered ringmoiety is a thermoplastic copolymer having(1) a repeating unit derivedfrom methyl methacrylate, (2) at least one repeating unit selected fromthe group consisting of a repeating unit derived from methacrylic acidand a repeating unit derived from acrylic acid, and (3) a repeating unitderived from an acid anhydride of six-membered ring having the formula,##STR9## wherein R and R' are independently methyl or hydrogen, and thecontent of the repeating unit (1) in the copolymer being 10 to 95% byweight, the content of the repeating units (2) and (3) in the copolymerbeing 5 to 35% by weight, the weight ratio of the repeating unit (3) tothe repeating units (2) and (3) being 55 : 100 or more, and the reducedviscosity of the copolymer, when measured at 25° C. with 1 weight%dimethyl formamide solution, being 0.3 to 1.5 dl/g.
 21. Thethermoplastic resin composition of claim 3, wherein the thermoplasticcopolymer containing an acid anhydride six-membered ring moiety is athermoplastic copolymer having(1) a repeating unit derived from methylmethacrylate, (2) at least one repeating unit selected from the groupconsisting of a repeating unit derived from methacrylic acid and arepeating unit derived from acrylic acid, (3) a repeating unit derivedfrom an acid anhydride of six-membered ring having the formula,##STR10## wherein R and R' are independently methyl or hydrogen, and (4)a repeating unit derived from an ethylenic α,β-unsaturated monomer,thecontent of the repeating unit (1) in the copolymer being 10 to 95% byweight, the content of the repeating unit (4) in the copolymer being atmost 55% by weight, the content of the repeating units (2) and (3) inthe copolymer being 5 to 35% by weight, the weight ratio of therepeating unit (3) to the repeating units (2) and (3) being 55 : 100 ormore, and the reduced viscosity of the copolymer, when measured at 25°C. with 1 weight% dimethyl formamide solution, being 0.3 to 1.5 dl/g.22. The thermoplastic resin composition of claim 1, wherein the epoxygroup-containing copolymer (G) is a copolymer of an unsaturated epoxycompound and ethylene or a terpolymer of an unsaturated epoxy compound,ethylene and an ethylenic unsaturated compound other than ethylene. 23.The thermoplastic resin composition of claim 2, wherein the epoxygroup-containing copolymer (G) is a copolymer of an unsaturated epoxycompound and ethylene or a terpolymer of an unsaturated epoxy compound,ethylene and an ethylenic unsaturated compound other than ethylene. 24.The thermoplastic resin composition of claim 3, wherein the epoxygroup-containing copolymer (G) is a copolymer of an unsaturated epoxycompound and ethylene or a terpolymer of an unsaturated epoxy compound,ethylene and an ethylenic unsaturated compound other than ethylene. 25.The thermoplastic resin composition of claim 1, wherein the startingmaterial for the rubbery substance (I) or the modified rubbery substance(H) is an ethylenic copolymer rubber.
 26. The thermoplastic resincomposition of claim 3, wherein the starting material for the rubberysubstance (I) or the modified rubbery substance (H) is an ethyleniccopolymer rubber.
 27. The thermoplastic resin composition of claim 1,wherein the component (i) is (a) a modified polypropylene (A) to whichhas been graft copolymerized an unsaturated carboxylic acid or aderivative thereof.
 28. The thermoplastic resin composition of claim 2,wherein the component (i) is (a) a modified polypropylene (A) to whichhas been graft copolymerized an unsaturated carboxylic acid or aderivative thereof.